zram: delay pending free request in read path
zram: delay pending free request in read path

Sergey reported we don't need to handle pending free request every I/O
so that this patch removes it in read path while we remain it in write
path.

Let's consider below example.

Swap subsystem ask to zram "A" block free by swap_slot_free_notify but
zram had been pended it without real freeing.  Swap subsystem allocates
"A" block for new data but request pended for a long time just handled
and zram blindly free new data on the "A" block.  :(

That's why we couldn't remove handle pending free request right before
zram-write.

Signed-off-by: Minchan Kim <eee62f459f15dcddf87a8df69e8328e2a2562028@kernel.org>
Reported-by: Sergey Senozhatsky <d9c384f6b6e27869ff3b53bd225c29030ac4166b@gmail.com>
Tested-by: Sergey Senozhatsky <d9c384f6b6e27869ff3b53bd225c29030ac4166b@gmail.com>
Cc: Nitin Gupta <cc4fec8a34766005dd45d48be045c08d736c11ed@vflare.org>
Cc: Jerome Marchand <d3643b417d7bb29446cdadf5ebe2f94cac95db45@redhat.com>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs