diff options
| author | Alex Dubov <oakad@yahoo.com> | 2011-01-12 17:01:04 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-13 08:03:22 -0800 |
| commit | d8256d487840f9c2c372f8fc615a5d378bc133f1 (patch) | |
| tree | c9b17bcf583e047ecb55bf775b55053c85b21935 | |
| parent | 8930c8aa740b12ad69f44a35137bcc39bfa3dc41 (diff) | |
| download | lwn-d8256d487840f9c2c372f8fc615a5d378bc133f1.tar.gz lwn-d8256d487840f9c2c372f8fc615a5d378bc133f1.zip | |
memstick: avert possible race condition between idr_pre_get and idr_get_new
Implement the usual pattern around idr_pre_get() and idr_get_new() to
handlethe situation where another thread concurrently steals this thread's
idr_pre_get() preallocation.
Signed-off-by: Alex Dubov <oakad@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/memstick/core/memstick.c | 18 | ||||
| -rw-r--r-- | drivers/memstick/core/mspro_block.c | 6 |
2 files changed, 15 insertions, 9 deletions
diff --git a/drivers/memstick/core/memstick.c b/drivers/memstick/core/memstick.c index 4303b7ef73e2..e9a3eab7b0cf 100644 --- a/drivers/memstick/core/memstick.c +++ b/drivers/memstick/core/memstick.c @@ -511,14 +511,18 @@ int memstick_add_host(struct memstick_host *host) { int rc; - if (!idr_pre_get(&memstick_host_idr, GFP_KERNEL)) - return -ENOMEM; + while (1) { + if (!idr_pre_get(&memstick_host_idr, GFP_KERNEL)) + return -ENOMEM; - spin_lock(&memstick_host_lock); - rc = idr_get_new(&memstick_host_idr, host, &host->id); - spin_unlock(&memstick_host_lock); - if (rc) - return rc; + spin_lock(&memstick_host_lock); + rc = idr_get_new(&memstick_host_idr, host, &host->id); + spin_unlock(&memstick_host_lock); + if (!rc) + break; + else if (rc != -EAGAIN) + return rc; + } dev_set_name(&host->dev, "memstick%u", host->id); diff --git a/drivers/memstick/core/mspro_block.c b/drivers/memstick/core/mspro_block.c index 02362eccc588..a167938d4517 100644 --- a/drivers/memstick/core/mspro_block.c +++ b/drivers/memstick/core/mspro_block.c @@ -1206,10 +1206,12 @@ static int mspro_block_init_disk(struct memstick_dev *card) msb->page_size = be16_to_cpu(sys_info->unit_size); - if (!idr_pre_get(&mspro_block_disk_idr, GFP_KERNEL)) + mutex_lock(&mspro_block_disk_lock); + if (!idr_pre_get(&mspro_block_disk_idr, GFP_KERNEL)) { + mutex_unlock(&mspro_block_disk_lock); return -ENOMEM; + } - mutex_lock(&mspro_block_disk_lock); rc = idr_get_new(&mspro_block_disk_idr, card, &disk_id); mutex_unlock(&mspro_block_disk_lock); |