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e3b7df65e0
add note about the need for deadlock-free sk_buff allocation Signed-off-by: Ed L. Cashin <ecashin@coraid.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
14 lines
788 B
Text
14 lines
788 B
Text
There is a potential for deadlock when allocating a struct sk_buff for
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data that needs to be written out to aoe storage. If the data is
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being written from a dirty page in order to free that page, and if
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there are no other pages available, then deadlock may occur when a
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free page is needed for the sk_buff allocation. This situation has
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not been observed, but it would be nice to eliminate any potential for
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deadlock under memory pressure.
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Because ATA over Ethernet is not fragmented by the kernel's IP code,
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the destructore member of the struct sk_buff is available to the aoe
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driver. By using a mempool for allocating all but the first few
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sk_buffs, and by registering a destructor, we should be able to
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efficiently allocate sk_buffs without introducing any potential for
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deadlock.
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