diff options
| author | James Hogan <james.hogan@imgtec.com> | 2011-06-24 13:55:10 +0100 |
|---|---|---|
| committer | Chris Ball <cjb@laptop.org> | 2011-07-20 17:20:58 -0400 |
| commit | 7456caae37396fc1bc6f8e9461d07664b8c2f280 (patch) | |
| tree | 972f231756e8e766aa367689085a2834c7f6fcb4 /drivers/mmc/host | |
| parent | b40af3aa7712e8f1b73e00e781cd93181483f649 (diff) | |
mmc: dw_mmc: fix race with request and removal
When a request is made, the card presence is checked and the request is
queued. These two parts must be atomic with respect to card removal, or
a card removal could be handled in between, and the new request wouldn't
get cancelled until another card was inserted. Therefore move the
spinlock protection from dw_mci_queue_request() up into dw_mci_request()
to cover the presence check.
Note that the test_bit() used for the presence check isn't atomic
itself, so should have been protected by a spinlock anyway.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Will Newton <will.newton@imgtec.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
Diffstat (limited to 'drivers/mmc/host')
| -rw-r--r-- | drivers/mmc/host/dw_mmc.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index 08c0592ed9bc..c4bddf6a5f1f 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -625,13 +625,13 @@ static void dw_mci_start_request(struct dw_mci *host, host->stop_cmdr = dw_mci_prepare_command(slot->mmc, mrq->stop); } +/* must be called with host->lock held */ static void dw_mci_queue_request(struct dw_mci *host, struct dw_mci_slot *slot, struct mmc_request *mrq) { dev_vdbg(&slot->mmc->class_dev, "queue request: state=%d\n", host->state); - spin_lock_bh(&host->lock); slot->mrq = mrq; if (host->state == STATE_IDLE) { @@ -640,8 +640,6 @@ static void dw_mci_queue_request(struct dw_mci *host, struct dw_mci_slot *slot, } else { list_add_tail(&slot->queue_node, &host->queue); } - - spin_unlock_bh(&host->lock); } static void dw_mci_request(struct mmc_host *mmc, struct mmc_request *mrq) @@ -651,14 +649,23 @@ static void dw_mci_request(struct mmc_host *mmc, struct mmc_request *mrq) WARN_ON(slot->mrq); + /* + * The check for card presence and queueing of the request must be + * atomic, otherwise the card could be removed in between and the + * request wouldn't fail until another card was inserted. + */ + spin_lock_bh(&host->lock); + if (!test_bit(DW_MMC_CARD_PRESENT, &slot->flags)) { + spin_unlock_bh(&host->lock); mrq->cmd->error = -ENOMEDIUM; mmc_request_done(mmc, mrq); return; } - /* We don't support multiple blocks of weird lengths. */ dw_mci_queue_request(host, slot, mrq); + + spin_unlock_bh(&host->lock); } static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) |