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2014-12-09sunrpc: require svc_create callers to pass in meaningful shutdown routineJeff Layton
Currently all svc_create callers pass in NULL for the shutdown parm, which then gets fixed up to be svc_rpcb_cleanup if the service uses rpcbind. Simplify this by instead having the the only caller that requires it (lockd) pass in svc_rpcb_cleanup and get rid of the special casing. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-09sunrpc: have svc_wake_up only deal with pool 0Jeff Layton
The way that svc_wake_up works is a bit inefficient. It walks all of the available pools for a service and either wakes up a task in each one or sets the SP_TASK_PENDING flag in each one. When svc_wake_up is called, there is no need to wake up more than one thread to do this work. In practice, only lockd currently uses this function and it's single threaded anyway. Thus, this just boils down to doing a wake up of a thread in pool 0 or setting a single flag. Eliminate the for loop in this function and change it to just operate on pool 0. Also update the comments that sit above it and get rid of some code that has been commented out for years now. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-09sunrpc: convert sp_task_pending flag to use atomic bitopsJeff Layton
In a later patch, we'll want to be able to handle this flag without holding the sp_lock. Change this field to an unsigned long flags field, and declare a new flag in it that can be managed with atomic bitops. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-09sunrpc: move rq_cachetype field to better optimize spaceJeff Layton
There are a couple of holes in the svc_rqst field on x86_64. Move the rq_cachetype to a different location to eliminate both of them. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-09sunrpc: move rq_splice_ok flag into rq_flagsJeff Layton
Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-09sunrpc: move rq_dropme flag into rq_flagsJeff Layton
Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-09sunrpc: move rq_usedeferral flag to rq_flagsJeff Layton
Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-09sunrpc: move rq_local field to rq_flagsJeff Layton
Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-09sunrpc: add a generic rq_flags field to svc_rqst and move rq_secure to itJeff Layton
In a later patch, we're going to need some atomic bit flags. Since that field will need to be an unsigned long, we mitigate that space consumption by migrating some other bitflags to the new field. Start with the rq_secure flag. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-09Merge tag 'nfs-for-3.19-1' into nfsd for-3.19 branchJ. Bruce Fields
Mainly what I need is 860a0d9e511f "sunrpc: add some tracepoints in svc_rqst handling functions", which subsequent server rpc patches from jlayton depend on. I'm merging this later tag on the assumption that's more likely to be a tested and stable point.
2014-12-01nfsd: minor off by one checks in __write_versions()Dan Carpenter
My static checker complains that if "len == remaining" then it means we have truncated the last character off the version string. The intent of the code is that we print as many versions as we can without truncating a version. Then we put a newline at the end. If the newline can't fit we return -EINVAL. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-01sunrpc: release svc_pool_map reference when serv allocation failsJeff Layton
Currently, it leaks when the allocation fails. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-01sunrpc: eliminate the XPT_DETACHED flagJeff Layton
All it does is indicate whether a xprt has already been deleted from a list or not, which is unnecessary since we use list_del_init and it's always set and checked under the sv_lock anyway. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-11-27sunrpc: add a debugfs rpc_xprt directory with an info file in itJeff Layton
Add a new directory heirarchy under the debugfs sunrpc/ directory: sunrpc/ rpc_xprt/ <xprt id>/ Within that directory, we can put files that give info about the xprts. We do have the (minor) problem that there is no succinct, unique identifier for rpc_xprts. So we generate them synthetically with a static atomic_t counter. For now, this directory just holds an "info" file, but we may add other files to it in the future. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-27sunrpc: add debugfs file for displaying client rpc_task queueJeff Layton
It's possible to get a dump of the RPC task queue by writing a value to /proc/sys/sunrpc/rpc_debug. If you write any value to that file, you get a dump of the RPC client task list into the log buffer. This is a rather inconvenient interface however, and makes it hard to get immediate info about the task queue. Add a new directory hierarchy under debugfs: sunrpc/ rpc_clnt/ <clientid>/ Within each clientid directory we create a new "tasks" file that will dump info similar to what shows up in the log buffer, but with a few small differences -- we avoid printing raw kernel addresses in favor of symbolic names and the XID is also displayed. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-26Merge tag 'nfs-rdma-for-3.19' of ↵Trond Myklebust
git://git.linux-nfs.org/projects/anna/nfs-rdma into linux-next Pull NFS client RDMA changes for 3.19 from Anna Schumaker: "NFS: Client side changes for RDMA These patches various bugfixes and cleanups for using NFS over RDMA, including better error handling and performance improvements by using pad optimization. Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>" * tag 'nfs-rdma-for-3.19' of git://git.linux-nfs.org/projects/anna/nfs-rdma: xprtrdma: Display async errors xprtrdma: Enable pad optimization xprtrdma: Re-write rpcrdma_flush_cqs() xprtrdma: Refactor tasklet scheduling xprtrdma: unmap all FMRs during transport disconnect xprtrdma: Cap req_cqinit xprtrdma: Return an errno from rpcrdma_register_external()
2014-11-26Merge tag 'nfs-cel-for-3.19' of ↵Trond Myklebust
git://git.linux-nfs.org/projects/anna/nfs-rdma into linux-next Pull pull additional NFS client changes for 3.19 from Anna Schumaker: "NFS: Generic client side changes from Chuck These patches fixes for iostats and SETCLIENTID in addition to cleaning up the nfs4_init_callback() function. Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>" * tag 'nfs-cel-for-3.19' of git://git.linux-nfs.org/projects/anna/nfs-rdma: NFS: Clean up nfs4_init_callback() NFS: SETCLIENTID XDR buffer sizes are incorrect SUNRPC: serialize iostats updates
2014-11-25nfs: Add DEALLOCATE supportAnna Schumaker
This patch adds support for using the NFS v4.2 operation DEALLOCATE to punch holes in a file. Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-25nfs: Add ALLOCATE supportAnna Schumaker
This patch adds support for using the NFS v4.2 operation ALLOCATE to preallocate data in a file. Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-25NFS: Clean up nfs4_init_callback()Chuck Lever
nfs4_init_callback() is never invoked for NFS versions other than 4. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2014-11-25NFS: SETCLIENTID XDR buffer sizes are incorrectChuck Lever
Use the correct calculation of the maximum size of a clientaddr4 when encoding and decoding SETCLIENTID operations. clientaddr4 is defined in section 2.2.10 of RFC3530bis-31. The usage in encode_setclientid_maxsz is missing the 4-byte length in both strings, but is otherwise correct. decode_setclientid_maxsz simply asks for a page of receive buffer space, which is unnecessarily large (more than 4KB). Note that a SETCLIENTID reply is either clientid+verifier, or clientaddr4, depending on the returned NFS status. It doesn't hurt to allocate enough space for both. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2014-11-25SUNRPC: serialize iostats updatesChuck Lever
Occasionally mountstats reports a negative retransmission rate. Ensure that two RPCs completing concurrently don't confuse the sums in the transport's op_metrics array. Since pNFS filelayout can invoke rpc_count_iostats() on another transport from xprt_release(), we can't rely on simply holding the transport_lock in xprt_release(). There's nothing for it but hard serialization. One spin lock per RPC operation should make this as painless as it can be. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2014-11-25xprtrdma: Display async errorsChuck Lever
An async error upcall is a hard error, and should be reported in the system log. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2014-11-25xprtrdma: Enable pad optimizationChuck Lever
The Linux NFS/RDMA server used to reject NFSv3 WRITE requests when pad optimization was enabled. That bug was fixed by commit e560e3b510d2 ("svcrdma: Add zero padding if the client doesn't send it"). We can now enable pad optimization on the client, which helps performance and is supported now by both Linux and Solaris servers. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2014-11-25xprtrdma: Re-write rpcrdma_flush_cqs()Chuck Lever
Currently rpcrdma_flush_cqs() attempts to avoid code duplication, and simply invokes rpcrdma_recvcq_upcall and rpcrdma_sendcq_upcall. 1. rpcrdma_flush_cqs() can run concurrently with provider upcalls. Both flush_cqs() and the upcalls were invoking ib_poll_cq() in different threads using the same wc buffers (ep->rep_recv_wcs and ep->rep_send_wcs), added by commit 1c00dd077654 ("xprtrmda: Reduce calls to ib_poll_cq() in completion handlers"). During transport disconnect processing, this sometimes resulted in the same reply getting added to the rpcrdma_tasklets_g list more than once, which corrupted the list. 2. The upcall functions drain only a limited number of CQEs, thanks to the poll budget added by commit 8301a2c047cc ("xprtrdma: Limit work done by completion handler"). Fixes: a7bc211ac926 ("xprtrdma: On disconnect, don't ignore ... ") BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=276 Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2014-11-25xprtrdma: Refactor tasklet schedulingChuck Lever
Restore the separate function that schedules the reply handling tasklet. I need to call it from two different paths. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2014-11-25xprtrdma: unmap all FMRs during transport disconnectChuck Lever
When using RPCRDMA_MTHCAFMR memory registration, after a few transport disconnect / reconnect cycles, ib_map_phys_fmr() starts to return EINVAL because the provider has exhausted its map pool. Make sure that all FMRs are unmapped during transport disconnect, and that ->send_request remarshals them during an RPC retransmit. This resets the transport's MRs to ensure that none are leaked during a disconnect. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2014-11-25xprtrdma: Cap req_cqinitChuck Lever
Recent work made FRMR registration and invalidation completions unsignaled. This greatly reduces the adapter interrupt rate. Every so often, however, a posted send Work Request is allowed to signal. Otherwise, the provider's Work Queue will wrap and the workload will hang. The number of Work Requests that are allowed to remain unsignaled is determined by the value of req_cqinit. Currently, this is set to the size of the send Work Queue divided by two, minus 1. For FRMR, the send Work Queue is the maximum number of concurrent RPCs (currently 32) times the maximum number of Work Requests an RPC might use (currently 7, though some adapters may need more). For mlx4, this is 224 entries. This leaves completion signaling disabled for 111 send Work Requests. Some providers hold back dispatching Work Requests until a CQE is generated. If completions are disabled, then no CQEs are generated for quite some time, and that can stall the Work Queue. I've seen this occur running xfstests generic/113 over NFSv4, where eventually, posting a FAST_REG_MR Work Request fails with -ENOMEM because the Work Queue has overflowed. The connection is dropped and re-established. Cap the rep_cqinit setting so completions are not left turned off for too long. BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=269 Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2014-11-25xprtrdma: Return an errno from rpcrdma_register_external()Chuck Lever
The RPC/RDMA send_request method and the chunk registration code expects an errno from the registration function. This allows the upper layers to distinguish between a recoverable failure (for example, temporary memory exhaustion) and a hard failure (for example, a bug in the registration logic). Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2014-11-24nfs: define nfs_inc_fscache_stats and using it as possibleLi RongQing
Define and use nfs_inc_fscache_stats when plus one, which can save to pass one parameter. Signed-off-by: Li RongQing <roy.qing.li@gmail.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24nfs: replace nfs_add_stats with nfs_inc_stats when add oneLi RongQing
Signed-off-by: Li RongQing <roy.qing.li@gmail.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24NFS: Deletion of unnecessary checks before the function call "nfs_put_client"Markus Elfring
The nfs_put_client() function tests whether its argument is NULL and then returns immediately. Thus the test around the call is not needed. This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24sunrpc: eliminate RPC_TRACEPOINTSJeff Layton
It's always set to the same value as CONFIG_TRACEPOINTS, so we can just use that instead. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24sunrpc: eliminate RPC_DEBUGJeff Layton
It's always set to whatever CONFIG_SUNRPC_DEBUG is, so just use that. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24lockd: eliminate LOCKD_DEBUGJeff Layton
LOCKD_DEBUG is always the same value as CONFIG_SUNRPC_DEBUG, so we can just use it instead. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24nfs41: fix nfs4_proc_layoutget error handlingPeng Tao
nfs4_layoutget_release() drops layout hdr refcnt. Grab the refcnt early so that it is safe to call .release in case nfs4_alloc_pages fails. Signed-off-by: Peng Tao <tao.peng@primarydata.com> Fixes: a47970ff78147 ("NFSv4.1: Hold reference to layout hdr in layoutget") Cc: stable@vger.kernel.org # 3.9+ Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24NFS: fix subtle change in COMMIT behaviorWeston Andros Adamson
Recent work in the pgio layer made it possible for there to be more than one request per page. This caused a subtle change in commit behavior, because write.c:nfs_commit_unstable_pages compares the number of *pages* waiting for writeback against the number of requests on a commit list to choose when to send a COMMIT in a non-blocking flush. This is probably hard to hit in normal operation - you have to be using rsize/wsize < PAGE_SIZE, or pnfs with lots of boundaries that are not page aligned to have a noticeable change in behavior. Signed-off-by: Weston Andros Adamson <dros@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24pnfs/blocklayout: fix end calculation in pnfs_num_cont_bytesChristoph Hellwig
Use the number of pages in the pagecache mapping instead of the number of pnfs requests which is only slightly related. Reported-by: Weston Andros Adamson <dros@primarydata.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24sunrpc: add tracepoints in xs_tcp_data_recvJeff Layton
Add tracepoints inside the main loop on xs_tcp_data_recv that allow us to keep an eye on what's happening during each phase of it. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24sunrpc: add new tracepoints in xprt handling codeJeff Layton
...so we can keep track of when calls are sent and replies received. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24sunrpc: add some tracepoints in svc_rqst handling functionsJeff Layton
...just around svc_send, svc_recv and svc_process for now. Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24NFS: Use nfs_server_capable() for checknig NFS_CAP_SEEKAnna Schumaker
This should make the code easier to maintain in the future. Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24nfs: Remove dead case from nfs4_map_errors()Jan Kara
NFS4ERR_ACCESS has number 13 and thus is matched and returned immediately at the beginning of nfs4_map_errors() and there's no point in checking it later. Coverity-id: 733891 Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-23Linux 3.18-rc6Linus Torvalds
2014-11-23uprobes, x86: Fix _TIF_UPROBE vs _TIF_NOTIFY_RESUMEAndy Lutomirski
x86 call do_notify_resume on paranoid returns if TIF_UPROBE is set but not on non-paranoid returns. I suspect that this is a mistake and that the code only works because int3 is paranoid. Setting _TIF_NOTIFY_RESUME in the uprobe code was probably a workaround for the x86 bug. With that bug fixed, we can remove _TIF_NOTIFY_RESUME from the uprobes code. Reported-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Borislav Petkov <bp@suse.de> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-11-23sched: Provide update_curr callbacks for stop/idle scheduling classesThomas Gleixner
Chris bisected a NULL pointer deference in task_sched_runtime() to commit 6e998916dfe3 'sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency'. Chris observed crashes in atop or other /proc walking programs when he started fork bombs on his machine. He assumed that this is a new exit race, but that does not make any sense when looking at that commit. What's interesting is that, the commit provides update_curr callbacks for all scheduling classes except stop_task and idle_task. While nothing can ever hit that via the clock_nanosleep() and clock_gettime() interfaces, which have been the target of the commit in question, the author obviously forgot that there are other code paths which invoke task_sched_runtime() do_task_stat(() thread_group_cputime_adjusted() thread_group_cputime() task_cputime() task_sched_runtime() if (task_current(rq, p) && task_on_rq_queued(p)) { update_rq_clock(rq); up->sched_class->update_curr(rq); } If the stats are read for a stomp machine task, aka 'migration/N' and that task is current on its cpu, this will happily call the NULL pointer of stop_task->update_curr. Ooops. Chris observation that this happens faster when he runs the fork bomb makes sense as the fork bomb will kick migration threads more often so the probability to hit the issue will increase. Add the missing update_curr callbacks to the scheduler classes stop_task and idle_task. While idle tasks cannot be monitored via /proc we have other means to hit the idle case. Fixes: 6e998916dfe3 'sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency' Reported-by: Chris Mason <clm@fb.com> Reported-and-tested-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-11-23Merge branch 'x86-traps' (trap handling from Andy Lutomirski)Linus Torvalds
Merge x86-64 iret fixes from Andy Lutomirski: "This addresses the following issues: - an unrecoverable double-fault triggerable with modify_ldt. - invalid stack usage in espfix64 failed IRET recovery from IST context. - invalid stack usage in non-espfix64 failed IRET recovery from IST context. It also makes a good but IMO scary change: non-espfix64 failed IRET will now report the correct error. Hopefully nothing depended on the old incorrect behavior, but maybe Wine will get confused in some obscure corner case" * emailed patches from Andy Lutomirski <luto@amacapital.net>: x86_64, traps: Rework bad_iret x86_64, traps: Stop using IST for #SS x86_64, traps: Fix the espfix64 #DF fixup and rewrite it in C
2014-11-23x86_64, traps: Rework bad_iretAndy Lutomirski
It's possible for iretq to userspace to fail. This can happen because of a bad CS, SS, or RIP. Historically, we've handled it by fixing up an exception from iretq to land at bad_iret, which pretends that the failed iret frame was really the hardware part of #GP(0) from userspace. To make this work, there's an extra fixup to fudge the gs base into a usable state. This is suboptimal because it loses the original exception. It's also buggy because there's no guarantee that we were on the kernel stack to begin with. For example, if the failing iret happened on return from an NMI, then we'll end up executing general_protection on the NMI stack. This is bad for several reasons, the most immediate of which is that general_protection, as a non-paranoid idtentry, will try to deliver signals and/or schedule from the wrong stack. This patch throws out bad_iret entirely. As a replacement, it augments the existing swapgs fudge into a full-blown iret fixup, mostly written in C. It's should be clearer and more correct. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-11-23x86_64, traps: Stop using IST for #SSAndy Lutomirski
On a 32-bit kernel, this has no effect, since there are no IST stacks. On a 64-bit kernel, #SS can only happen in user code, on a failed iret to user space, a canonical violation on access via RSP or RBP, or a genuine stack segment violation in 32-bit kernel code. The first two cases don't need IST, and the latter two cases are unlikely fatal bugs, and promoting them to double faults would be fine. This fixes a bug in which the espfix64 code mishandles a stack segment violation. This saves 4k of memory per CPU and a tiny bit of code. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-11-23x86_64, traps: Fix the espfix64 #DF fixup and rewrite it in CAndy Lutomirski
There's nothing special enough about the espfix64 double fault fixup to justify writing it in assembly. Move it to C. This also fixes a bug: if the double fault came from an IST stack, the old asm code would return to a partially uninitialized stack frame. Fixes: 3891a04aafd668686239349ea58f3314ea2af86b Signed-off-by: Andy Lutomirski <luto@amacapital.net> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>