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Petersen" , linux-scsi@vger.kernel.org, linux-block@vger.kernel.org, "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , "Ewan D. Milne" , Laurence Oberman Subject: Re: [PATCH] scsi: storvsc: set max_segment_size as UINT_MAX explicitly Message-ID: References: <20250616160509.52491-1-ming.lei@redhat.com> <20250617050240.GA2178@lst.de> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250617050240.GA2178@lst.de> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 On Tue, Jun 17, 2025 at 07:02:40AM +0200, Christoph Hellwig wrote: > Please try this proper fix instead: > > diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c > index e021f1106bea..09f5fb5b2fb1 100644 > --- a/drivers/scsi/hosts.c > +++ b/drivers/scsi/hosts.c > @@ -473,7 +473,9 @@ struct Scsi_Host *scsi_host_alloc(const struct scsi_host_template *sht, int priv > else > shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS; > > - if (sht->max_segment_size) > + if (sht->virt_boundary_mask) > + shost->virt_boundary_mask = sht->virt_boundary_mask; > + else if (sht->max_segment_size) > shost->max_segment_size = sht->max_segment_size; > else > shost->max_segment_size = BLK_MAX_SEGMENT_SIZE; This way works, but I prefer to set it explicitly in driver, instead of making block layer more fragile to deal with def ->max_segment_size if ->virt_boundary_mask is defined - for low level driver, if ->virt_boundary_mask is defined, ->max_segment_size should be UINT_MAX obviously since it implies single `virt segment`. Setting UINT_MAX in driver has document benefit too. - for logical block device(md, dm, ...), both ->virt_boundary_mask and ->max_segment_size may be set, and it is fine since logical block device driver needn't to deal with sg Thanks, Ming