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Commit d8256d48 authored by Alex Dubov's avatar Alex Dubov Committed by Linus Torvalds
Browse files

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: default avatarAlex Dubov <oakad@yahoo.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8930c8aa

drivers/memstick/core/memstick.c

+11 −7
Original line number Diff line number Diff line
@@ -511,14 +511,18 @@ int memstick_add_host(struct memstick_host *host) 
{

	int rc;



	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)

		if (!rc)

			break;

		else if (rc != -EAGAIN)

			return rc;

	}



	dev_set_name(&host->dev, "memstick%u", host->id);

drivers/memstick/core/mspro_block.c

+4 −2
Original line number Diff line number Diff line
@@ -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);