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From: Bart Van Assche <bvanassche@acm.org>
To: Arthur Simchaev <Arthur.Simchaev@wdc.com>, martin.petersen@oracle.com
Cc: beanhuo@micron.com, linux-scsi@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 4/4] ufs: core: Remove ufshcd_map_desc_id_to_length function
Date: Sun, 11 Dec 2022 16:18:59 -0800	[thread overview]
Message-ID: <71a10a4c-a726-edac-c5d3-1bfded690503@acm.org> (raw)
In-Reply-To: <1670763911-8695-5-git-send-email-Arthur.Simchaev@wdc.com>

On 12/11/22 05:05, Arthur Simchaev wrote:
> There shouldn't be any restriction of the descriptor size
> (not the descriptor id for that matter) up to QUERY_DESC_MAX_SIZE.
> According to the spec, the caller can use any descriptor size,
> and it is up to the device to return the actual size.
> Therefore there shouldn't be any sizes hardcoded in the kernel,
> nor any need to cache it, hence ufshcd_map_desc_id_to_length function is
> redundant. Always read the descriptors with QUERY_DESC_MAX_SIZE size.
> 
> Reviewed-by: Bart Van Assche <bvanassche@acm.org>

I have not yet replied with "Reviewed-by" to this patch so you are not
yet allowed to add my Reviewed-by tag to this patch.

> +	/* Update descriptor length */
> +	buff_len = desc_buf[QUERY_DESC_LENGTH_OFFSET];

Should a check be added here that desc_buf[QUERY_DESC_LENGTH_OFFSET]
<= QUERY_DESC_MAX_SIZE to protect against firmware bugs? Since
QUERY_DESC_MAX_SIZE == 255, adding BUILD_BUG_ON(QUERY_DESC_SIZE != 255)
and a comment may be sufficient.

Thanks,

Bart.

  reply	other threads:[~2022-12-12  0:19 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-11 13:05 [PATCH v5 0/4] ufs: core: Always read the descriptors with max length Arthur Simchaev
2022-12-11 13:05 ` [PATCH v5 1/4] ufs: core: Remove redundant wb check Arthur Simchaev
2022-12-13  5:32   ` Stanley Chu
2022-12-11 13:05 ` [PATCH v5 2/4] ufs: core: Remove redundant desc_size variable from hba Arthur Simchaev
2022-12-12  0:11   ` Bart Van Assche
2022-12-11 13:05 ` [PATCH v5 3/4] ufs: core: Remove len parameter from ufshcd_set_active_icc_lvl Arthur Simchaev
2022-12-11 13:05 ` [PATCH v5 4/4] ufs: core: Remove ufshcd_map_desc_id_to_length function Arthur Simchaev
2022-12-12  0:18   ` Bart Van Assche [this message]
2022-12-12  9:10     ` Arthur Simchaev
2022-12-12 19:25       ` Bart Van Assche
2022-12-12 19:26   ` Bart Van Assche
2022-12-30 21:50 ` [PATCH v5 0/4] ufs: core: Always read the descriptors with max length Martin K. Petersen

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