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-rw-r--r--drivers/usb/storage/protocol.c27
1 files changed, 15 insertions, 12 deletions
diff --git a/drivers/usb/storage/protocol.c b/drivers/usb/storage/protocol.c
index a41ce21c0697..958f5b17847c 100644
--- a/drivers/usb/storage/protocol.c
+++ b/drivers/usb/storage/protocol.c
@@ -150,13 +150,14 @@ void usb_stor_transparent_scsi_command(struct scsi_cmnd *srb,
150 150
151/* Copy a buffer of length buflen to/from the srb's transfer buffer. 151/* Copy a buffer of length buflen to/from the srb's transfer buffer.
152 * Update the **sgptr and *offset variables so that the next copy will 152 * Update the **sgptr and *offset variables so that the next copy will
153 * pick up from where this one left off. */ 153 * pick up from where this one left off.
154 154 */
155unsigned int usb_stor_access_xfer_buf(unsigned char *buffer, 155unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
156 unsigned int buflen, struct scsi_cmnd *srb, struct scatterlist **sgptr, 156 unsigned int buflen, struct scsi_cmnd *srb, struct scatterlist **sgptr,
157 unsigned int *offset, enum xfer_buf_dir dir) 157 unsigned int *offset, enum xfer_buf_dir dir)
158{ 158{
159 unsigned int cnt; 159 unsigned int cnt;
160 struct scatterlist *sg = *sgptr;
160 161
161 /* We have to go through the list one entry 162 /* We have to go through the list one entry
162 * at a time. Each s-g entry contains some number of pages, and 163 * at a time. Each s-g entry contains some number of pages, and
@@ -164,22 +165,23 @@ unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
164 * in kernel-addressable memory then kmap() will return its address. 165 * in kernel-addressable memory then kmap() will return its address.
165 * If the page is not directly accessible -- such as a user buffer 166 * If the page is not directly accessible -- such as a user buffer
166 * located in high memory -- then kmap() will map it to a temporary 167 * located in high memory -- then kmap() will map it to a temporary
167 * position in the kernel's virtual address space. */ 168 * position in the kernel's virtual address space.
168 struct scatterlist *sg = *sgptr; 169 */
169 170
170 if (!sg) 171 if (!sg)
171 sg = scsi_sglist(srb); 172 sg = scsi_sglist(srb);
173 buflen = min(buflen, scsi_bufflen(srb));
172 174
173 /* This loop handles a single s-g list entry, which may 175 /* This loop handles a single s-g list entry, which may
174 * include multiple pages. Find the initial page structure 176 * include multiple pages. Find the initial page structure
175 * and the starting offset within the page, and update 177 * and the starting offset within the page, and update
176 * the *offset and **sgptr values for the next loop. */ 178 * the *offset and **sgptr values for the next loop.
179 */
177 cnt = 0; 180 cnt = 0;
178 while (cnt < buflen) { 181 while (cnt < buflen && sg) {
179 struct page *page = sg_page(sg) + 182 struct page *page = sg_page(sg) +
180 ((sg->offset + *offset) >> PAGE_SHIFT); 183 ((sg->offset + *offset) >> PAGE_SHIFT);
181 unsigned int poff = 184 unsigned int poff = (sg->offset + *offset) & (PAGE_SIZE-1);
182 (sg->offset + *offset) & (PAGE_SIZE-1);
183 unsigned int sglen = sg->length - *offset; 185 unsigned int sglen = sg->length - *offset;
184 186
185 if (sglen > buflen - cnt) { 187 if (sglen > buflen - cnt) {
@@ -222,14 +224,15 @@ unsigned int usb_stor_access_xfer_buf(unsigned char *buffer,
222} 224}
223 225
224/* Store the contents of buffer into srb's transfer buffer and set the 226/* Store the contents of buffer into srb's transfer buffer and set the
225 * SCSI residue. */ 227 * SCSI residue.
228 */
226void usb_stor_set_xfer_buf(unsigned char *buffer, 229void usb_stor_set_xfer_buf(unsigned char *buffer,
227 unsigned int buflen, struct scsi_cmnd *srb) 230 unsigned int buflen, struct scsi_cmnd *srb)
228{ 231{
229 unsigned int offset = 0; 232 unsigned int offset = 0;
230 struct scatterlist *sg = NULL; 233 struct scatterlist *sg = NULL;
231 234
232 usb_stor_access_xfer_buf(buffer, buflen, srb, &sg, &offset, 235 buflen = usb_stor_access_xfer_buf(buffer, buflen, srb, &sg, &offset,
233 TO_XFER_BUF); 236 TO_XFER_BUF);
234 if (buflen < scsi_bufflen(srb)) 237 if (buflen < scsi_bufflen(srb))
235 scsi_set_resid(srb, scsi_bufflen(srb) - buflen); 238 scsi_set_resid(srb, scsi_bufflen(srb) - buflen);