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>
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@ -511,14 +511,18 @@ int memstick_add_host(struct memstick_host *host)
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{
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int rc;
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while (1) {
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if (!idr_pre_get(&memstick_host_idr, GFP_KERNEL))
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return -ENOMEM;
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spin_lock(&memstick_host_lock);
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rc = idr_get_new(&memstick_host_idr, host, &host->id);
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spin_unlock(&memstick_host_lock);
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if (rc)
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if (!rc)
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break;
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else if (rc != -EAGAIN)
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return rc;
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}
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dev_set_name(&host->dev, "memstick%u", host->id);
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@ -1206,10 +1206,12 @@ static int mspro_block_init_disk(struct memstick_dev *card)
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msb->page_size = be16_to_cpu(sys_info->unit_size);
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if (!idr_pre_get(&mspro_block_disk_idr, GFP_KERNEL))
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return -ENOMEM;
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mutex_lock(&mspro_block_disk_lock);
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if (!idr_pre_get(&mspro_block_disk_idr, GFP_KERNEL)) {
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mutex_unlock(&mspro_block_disk_lock);
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return -ENOMEM;
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}
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rc = idr_get_new(&mspro_block_disk_idr, card, &disk_id);
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mutex_unlock(&mspro_block_disk_lock);
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