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[SCSI] usb: protocol - convert to accessors and !use_sg code path removal

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- Use scsi data accessors and remove of !use_sg code path

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Acked-by: Matthew Dharm <mdharm-scsi@one-eyed-alien.net>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
Boaz Harrosh 2007-09-09 20:22:23 +03:00 committed by James Bottomley
parent caa1e8c321
commit dd829d2302
1 changed files with 48 additions and 68 deletions
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116
drivers/usb/storage/protocol.c
View file

@ -149,11 +149,7 @@ void usb_stor_transparent_scsi_command(struct scsi_cmnd *srb,
***********************************************************************/
/* Copy a buffer of length buflen to/from the srb's transfer buffer.
* (Note: for scatter-gather transfers (srb->use_sg > 0), srb->request_buffer
* points to a list of s-g entries and we ignore srb->request_bufflen.
* For non-scatter-gather transfers, srb->request_buffer points to the
* transfer buffer itself and srb->request_bufflen is the buffer's length.)
* Update the *index and *offset variables so that the next copy will
* Update the **sgptr and *offset variables so that the next copy will
* pick up from where this one left off. */
unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
@ -162,80 +158,64 @@ unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
{
unsigned int cnt;
/* If not using scatter-gather, just transfer the data directly.
* Make certain it will fit in the available buffer space. */
if (srb->use_sg == 0) {
if (*offset >= srb->request_bufflen)
return 0;
cnt = min(buflen, srb->request_bufflen - *offset);
if (dir == TO_XFER_BUF)
memcpy((unsigned char *) srb->request_buffer + *offset,
buffer, cnt);
else
memcpy(buffer, (unsigned char *) srb->request_buffer +
*offset, cnt);
*offset += cnt;
/* Using scatter-gather. We have to go through the list one entry
/* We have to go through the list one entry
* at a time. Each s-g entry contains some number of pages, and
* each page has to be kmap()'ed separately. If the page is already
* in kernel-addressable memory then kmap() will return its address.
* If the page is not directly accessible -- such as a user buffer
* located in high memory -- then kmap() will map it to a temporary
* position in the kernel's virtual address space. */
} else {
struct scatterlist *sg = *sgptr;
struct scatterlist *sg = *sgptr;
if (!sg)
sg = (struct scatterlist *) srb->request_buffer;
if (!sg)
sg = scsi_sglist(srb);
/* This loop handles a single s-g list entry, which may
* include multiple pages. Find the initial page structure
* and the starting offset within the page, and update
* the *offset and *index values for the next loop. */
cnt = 0;
while (cnt < buflen) {
struct page *page = sg_page(sg) +
((sg->offset + *offset) >> PAGE_SHIFT);
unsigned int poff =
(sg->offset + *offset) & (PAGE_SIZE-1);
unsigned int sglen = sg->length - *offset;
/* This loop handles a single s-g list entry, which may
* include multiple pages. Find the initial page structure
* and the starting offset within the page, and update
* the *offset and **sgptr values for the next loop. */
cnt = 0;
while (cnt < buflen) {
struct page *page = sg_page(sg) +
((sg->offset + *offset) >> PAGE_SHIFT);
unsigned int poff =
(sg->offset + *offset) & (PAGE_SIZE-1);
unsigned int sglen = sg->length - *offset;
if (sglen > buflen - cnt) {
if (sglen > buflen - cnt) {
/* Transfer ends within this s-g entry */
sglen = buflen - cnt;
*offset += sglen;
} else {
/* Transfer ends within this s-g entry */
sglen = buflen - cnt;
*offset += sglen;
} else {
/* Transfer continues to next s-g entry */
*offset = 0;
sg = sg_next(sg);
}
/* Transfer the data for all the pages in this
* s-g entry. For each page: call kmap(), do the
* transfer, and call kunmap() immediately after. */
while (sglen > 0) {
unsigned int plen = min(sglen, (unsigned int)
PAGE_SIZE - poff);
unsigned char *ptr = kmap(page);
if (dir == TO_XFER_BUF)
memcpy(ptr + poff, buffer + cnt, plen);
else
memcpy(buffer + cnt, ptr + poff, plen);
kunmap(page);
/* Start at the beginning of the next page */
poff = 0;
++page;
cnt += plen;
sglen -= plen;
}
/* Transfer continues to next s-g entry */
*offset = 0;
sg = sg_next(sg);
}
/* Transfer the data for all the pages in this
* s-g entry. For each page: call kmap(), do the
* transfer, and call kunmap() immediately after. */
while (sglen > 0) {
unsigned int plen = min(sglen, (unsigned int)
PAGE_SIZE - poff);
unsigned char *ptr = kmap(page);
if (dir == TO_XFER_BUF)
memcpy(ptr + poff, buffer + cnt, plen);
else
memcpy(buffer + cnt, ptr + poff, plen);
kunmap(page);
/* Start at the beginning of the next page */
poff = 0;
++page;
cnt += plen;
sglen -= plen;
}
*sgptr = sg;
}
*sgptr = sg;
/* Return the amount actually transferred */
return cnt;
@ -251,6 +231,6 @@ void usb_stor_set_xfer_buf(unsigned char *buffer,
usb_stor_access_xfer_buf(buffer, buflen, srb, &sg, &offset,
TO_XFER_BUF);
if (buflen < srb->request_bufflen)
srb->resid = srb->request_bufflen - buflen;
if (buflen < scsi_bufflen(srb))
scsi_set_resid(srb, scsi_bufflen(srb) - buflen);
}