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From: Alberto Garcia <berto@igalia.com>
To: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
	qemu-block@nongnu.org
Cc: kwolf@redhat.com, fam@euphon.net, integration@gluster.org,
	sheepdog@lists.wpkg.org, pavel.dovgaluk@ispras.ru,
	dillaman@redhat.com, qemu-devel@nongnu.org, sw@weilnetz.de,
	pl@kamp.de, ronniesahlberg@gmail.com, mreitz@redhat.com,
	den@openvz.org, vsementsov@virtuozzo.com, stefanha@redhat.com,
	namei.unix@gmail.com, pbonzini@redhat.com, jsnow@redhat.com,
	ari@tuxera.com
Subject: Re: [PATCH v3 01/17] block/throttle-groups: throttle_group_co_io_limits_intercept(): 64bit bytes
Date: Mon, 11 May 2020 17:28:12 +0200	[thread overview]
Message-ID: <w51ftc6o5ir.fsf@maestria.local.igalia.com> (raw)
In-Reply-To: <20200430111033.29980-2-vsementsov@virtuozzo.com>

On Thu 30 Apr 2020 01:10:17 PM CEST, Vladimir Sementsov-Ogievskiy wrote:
> The function is called from 64bit io handlers, and bytes is just passed
> to throttle_account() which is 64bit too (unsigned though). So, let's
> convert intermediate argument to 64bit too.
>
> This patch is a first in the 64-bit-blocklayer series, so we are
> generally moving to int64_t for both offset and bytes parameters on all
> io paths. Main motivation is realization of 64-bit write_zeroes
> operation for fast zeroing large disk chunks, up to the whole disk.
>
> We chose signed type, to be consistent with off_t (which is signed) and
> with possibility for signed return type (where negative value means
> error).
>
> Patch-correctness audit by Eric Blake:
>
>   Caller has 32-bit, this patch now causes widening which is safe:
>   block/block-backend.c: blk_do_preadv() passes 'unsigned int'
>   block/block-backend.c: blk_do_pwritev_part() passes 'unsigned int'
>   block/throttle.c: throttle_co_pwrite_zeroes() passes 'int'
>   block/throttle.c: throttle_co_pdiscard() passes 'int'
>
>   Caller has 64-bit, this patch fixes potential bug where pre-patch
>   could narrow, except it's easy enough to trace that callers are still
>   capped at 2G actions:
>   block/throttle.c: throttle_co_preadv() passes 'uint64_t'
>   block/throttle.c: throttle_co_pwritev() passes 'uint64_t'
>
>   Implementation in question: block/throttle-groups.c
>   throttle_group_co_io_limits_intercept() takes 'unsigned int bytes'
>   and uses it: argument to util/throttle.c throttle_account(uint64_t)
>
>   All safe: it patches a latent bug, and does not introduce any 64-bit
>   gotchas once throttle_co_p{read,write}v are relaxed, and assuming
>   throttle_account() is not buggy.
>
> Series: 64bit-block-status
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>

Reviewed-by: Alberto Garcia <berto@igalia.com>

Berto


  reply	other threads:[~2020-05-11 15:29 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-30 11:10 [PATCH v3 00/17] 64bit block-layer Vladimir Sementsov-Ogievskiy
2020-04-30 11:10 ` [PATCH v3 01/17] block/throttle-groups: throttle_group_co_io_limits_intercept(): 64bit bytes Vladimir Sementsov-Ogievskiy
2020-05-11 15:28   ` Alberto Garcia [this message]
2020-04-30 11:10 ` [PATCH v3 02/17] block: use int64_t as bytes type in tracked requests Vladimir Sementsov-Ogievskiy
2020-05-11 15:32   ` Alberto Garcia
2020-05-22 19:09   ` Eric Blake
2020-04-30 11:10 ` [PATCH v3 03/17] block/io: use int64_t bytes parameter in bdrv_check_byte_request() Vladimir Sementsov-Ogievskiy
2020-05-11 15:57   ` Alberto Garcia
2020-04-30 11:10 ` [PATCH v3 04/17] block/io: use int64_t bytes in driver wrappers Vladimir Sementsov-Ogievskiy
2020-05-11 16:30   ` Alberto Garcia
2020-04-30 11:10 ` [PATCH v3 05/17] block/io: support int64_t bytes in bdrv_co_do_pwrite_zeroes() Vladimir Sementsov-Ogievskiy
2020-05-08 18:20   ` Eric Blake
2020-05-11 17:17   ` Alberto Garcia
2020-05-11 18:34     ` Eric Blake
2020-06-23 10:20       ` Vladimir Sementsov-Ogievskiy
2020-06-23 16:37         ` Eric Blake
2020-04-30 11:10 ` [PATCH v3 06/17] block/io: support int64_t bytes in bdrv_aligned_pwritev() Vladimir Sementsov-Ogievskiy
2020-05-08 20:38   ` Eric Blake
2020-06-18 14:29   ` Alberto Garcia
2020-04-30 11:10 ` [PATCH v3 07/17] block/io: support int64_t bytes in bdrv_co_do_copy_on_readv() Vladimir Sementsov-Ogievskiy
2020-05-21 22:29   ` Eric Blake
2020-05-22  6:30     ` Vladimir Sementsov-Ogievskiy
2020-04-30 11:10 ` [PATCH v3 08/17] block/io: support int64_t bytes in bdrv_aligned_preadv() Vladimir Sementsov-Ogievskiy
2020-05-22 15:14   ` Eric Blake
2020-06-18 14:35     ` Alberto Garcia
2020-06-18 14:47       ` Eric Blake
2020-04-30 11:10 ` [PATCH v3 09/17] block/io: support int64_t bytes in bdrv_co_p{read, write}v_part() Vladimir Sementsov-Ogievskiy
2020-05-22 19:34   ` [PATCH v3 09/17] block/io: support int64_t bytes in bdrv_co_p{read,write}v_part() Eric Blake
2020-04-30 11:10 ` [PATCH v3 10/17] block/io: support int64_t bytes in read/write wrappers Vladimir Sementsov-Ogievskiy
2020-04-30 11:10 ` [PATCH v3 11/17] block/io: use int64_t bytes in copy_range Vladimir Sementsov-Ogievskiy
2020-04-30 11:10 ` [PATCH v3 12/17] block/block-backend: convert blk io path to use int64_t parameters Vladimir Sementsov-Ogievskiy
2020-06-23 22:11   ` Eric Blake
2020-04-30 11:10 ` [PATCH v3 13/17] block: use int64_t instead of uint64_t in driver read handlers Vladimir Sementsov-Ogievskiy
2020-04-30 11:10 ` [PATCH v3 14/17] block: use int64_t instead of uint64_t in driver write handlers Vladimir Sementsov-Ogievskiy
2020-04-30 11:10 ` [PATCH v3 15/17] block: use int64_t instead of uint64_t in copy_range driver handlers Vladimir Sementsov-Ogievskiy
2020-04-30 11:10 ` [PATCH v3 16/17] block: use int64_t instead of int in driver write_zeroes handlers Vladimir Sementsov-Ogievskiy
2020-04-30 11:10 ` [PATCH v3 17/17] block: use int64_t instead of int in driver discard handlers Vladimir Sementsov-Ogievskiy
2020-05-06  6:40   ` Vladimir Sementsov-Ogievskiy
2020-04-30 20:51 ` [PATCH v3 00/17] 64bit block-layer no-reply
2020-05-06  6:39   ` Vladimir Sementsov-Ogievskiy
2020-04-30 20:57 ` no-reply
2020-12-01 16:07 ` Vladimir Sementsov-Ogievskiy
2020-12-01 16:56   ` Vladimir Sementsov-Ogievskiy
2020-12-01 21:50   ` Eric Blake

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