***********************************************************************/
/* 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,
{
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;
-
- if (!sg)
- sg = (struct scatterlist *) srb->request_buffer;
-
- /* 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;
-
- if (sglen > buflen - cnt) {
-
- /* 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;
- }
+ struct scatterlist *sg = *sgptr;
+
+ 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 **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) {
+
+ /* 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;
}
- *sgptr = sg;
}
+ *sgptr = sg;
/* Return the amount actually transferred */
return cnt;
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);
}
git.openpandora.org / pandora-kernel.git / blobdiff