ACK Other RAID drivers (eg: aacraid) makes the assumption that commands in these paths (INQUIRY, READ CAPACITY, MODE SENSE etc spoofing) are single scatter gather elements and have yet to be bitten. I agree with Fujita-san about the practical unlikelihood. The fix does not incur any change in code overhead, so it is worth hardening!
Can one create a request via /dev/sg for a buffer smaller than 256 and manage to create a multi-element scatter gather? Sincerely -- Mark Salyzyn > -----Original Message----- > From: FUJITA Tomonori [mailto:[EMAIL PROTECTED] > Sent: Tuesday, February 19, 2008 4:42 AM > To: [EMAIL PROTECTED] > Cc: linux-scsi@vger.kernel.org; Salyzyn, Mark; > [EMAIL PROTECTED]; [EMAIL PROTECTED] > Subject: [PATCH] ips: sg chaining support to the path to non > I/O commands > > Here is another ips patch, but not a bug fix. > > = > From: FUJITA Tomonori <[EMAIL PROTECTED]> > Subject: [PATCH] ips: sg chaining support to the path to non > I/O commands > > I overlooked ips_scmd_buf_write and ips_scmd_buf_read when I converted > ips to use the data buffer accessors. > > ips is unlikely to use sg chaining (especially in this path) since a) > this path is used only for non I/O commands (with little data > transfer), b) ips's sg_tablesize is set to just 17. > > Thanks to Tim Pepper for testing this patch. > > Signed-off-by: FUJITA Tomonori <[EMAIL PROTECTED]> > Cc: Salyzyn, Mark <[EMAIL PROTECTED]> > Cc: James Bottomley <[EMAIL PROTECTED]> > --- > drivers/scsi/ips.c | 18 ++++++++++-------- > 1 files changed, 10 insertions(+), 8 deletions(-) > > diff --git a/drivers/scsi/ips.c b/drivers/scsi/ips.c > index 7ed568f..e5467a4 100644 > --- a/drivers/scsi/ips.c > +++ b/drivers/scsi/ips.c > @@ -3510,15 +3510,16 @@ ips_scmd_buf_write(struct scsi_cmnd > *scmd, void *data, unsigned int count) > struct scatterlist *sg = scsi_sglist(scmd); > > for (i = 0, xfer_cnt = 0; > - (i < scsi_sg_count(scmd)) && (xfer_cnt < count); i++) { > - min_cnt = min(count - xfer_cnt, sg[i].length); > + (i < scsi_sg_count(scmd)) && (xfer_cnt < count); > + i++, sg = sg_next(sg)) { > + min_cnt = min(count - xfer_cnt, sg->length); > > /* kmap_atomic() ensures addressability of > the data buffer.*/ > /* local_irq_save() protects the KM_IRQ0 > address slot. */ > local_irq_save(flags); > - buffer = kmap_atomic(sg_page(&sg[i]), > KM_IRQ0) + sg[i].offset; > + buffer = kmap_atomic(sg_page(sg), KM_IRQ0) + > sg->offset; > memcpy(buffer, &cdata[xfer_cnt], min_cnt); > - kunmap_atomic(buffer - sg[i].offset, KM_IRQ0); > + kunmap_atomic(buffer - sg->offset, KM_IRQ0); > local_irq_restore(flags); > > xfer_cnt += min_cnt; > @@ -3543,15 +3544,16 @@ ips_scmd_buf_read(struct scsi_cmnd > *scmd, void *data, unsigned int count) > struct scatterlist *sg = scsi_sglist(scmd); > > for (i = 0, xfer_cnt = 0; > - (i < scsi_sg_count(scmd)) && (xfer_cnt < count); i++) { > - min_cnt = min(count - xfer_cnt, sg[i].length); > + (i < scsi_sg_count(scmd)) && (xfer_cnt < count); > + i++, sg = sg_next(sg)) { > + min_cnt = min(count - xfer_cnt, sg->length); > > /* kmap_atomic() ensures addressability of > the data buffer.*/ > /* local_irq_save() protects the KM_IRQ0 > address slot. */ > local_irq_save(flags); > - buffer = kmap_atomic(sg_page(&sg[i]), > KM_IRQ0) + sg[i].offset; > + buffer = kmap_atomic(sg_page(sg), KM_IRQ0) + > sg->offset; > memcpy(&cdata[xfer_cnt], buffer, min_cnt); > - kunmap_atomic(buffer - sg[i].offset, KM_IRQ0); > + kunmap_atomic(buffer - sg->offset, KM_IRQ0); > local_irq_restore(flags); > > xfer_cnt += min_cnt; - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
