[PATCH] PATCH: usb-storage: allocate separate sense buffer

This patch is from Alan Stern (as560). It has been rediffed against a current tree. This patch allocates a separate buffer for usb-storage to use when auto-sensing. Up to now we have been using the sense buffer embedded in a scsi_cmnd struct, which is dangerous on hosts that (a) don't do cache-coherent DMA or (b) have DMA alignment restrictions. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] PATCH: usb-storage: allocate separate sense buffer
This patch is from Alan Stern (as560). It has been rediffed against a current tree. This patch allocates a separate buffer for usb-storage to use when auto-sensing. Up to now we have been using the sense buffer embedded in a scsi_cmnd struct, which is dangerous on hosts that (a) don't do cache-coherent DMA or (b) have DMA alignment restrictions. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Alan Stern · Greg Kroah-Hartman
1 parent b876aef7f8
Showing 3 changed files with 13 additions and 2 deletions Side-by-side Diff
drivers/usb/storage/transport.c
drivers/usb/storage/usb.c
drivers/usb/storage/usb.h
@@ -636,11 +636,11 @@
  
 		/* use the new buffer we have */
 		old_request_buffer = srb->request_buffer;
-		srb->request_buffer = srb->sense_buffer;
+		srb->request_buffer = us->sensebuf;
  
 		/* set the buffer length for transfer */
 		old_request_bufflen = srb->request_bufflen;
-		srb->request_bufflen = 18;
+		srb->request_bufflen = US_SENSE_SIZE;
  
 		/* set up for no scatter-gather use */
 		old_sg = srb->use_sg;
@@ -652,6 +652,7 @@
 		temp_result = us->transport(us->srb, us);
  
 		/* let's clean up right away */
+		memcpy(srb->sense_buffer, us->sensebuf, US_SENSE_SIZE);
 		srb->resid = old_resid;
 		srb->request_buffer = old_request_buffer;
 		srb->request_bufflen = old_request_bufflen;
@@ -467,6 +467,12 @@
 		US_DEBUGP("I/O buffer allocation failed\n");
 		return -ENOMEM;
 	}
+
+	us->sensebuf = kmalloc(US_SENSE_SIZE, GFP_KERNEL);
+	if (!us->sensebuf) {
+		US_DEBUGP("Sense buffer allocation failed\n");
+		return -ENOMEM;
+	}
 	return 0;
 }
  
@@ -799,6 +805,8 @@
 static void dissociate_dev(struct us_data *us)
 {
 	US_DEBUGP("-- %s\n", __FUNCTION__);
+
+	kfree(us->sensebuf);
  
 	/* Free the device-related DMA-mapped buffers */
 	if (us->cr)
@@ -117,6 +117,7 @@
  */
  
 #define US_IOBUF_SIZE		64	/* Size of the DMA-mapped I/O buffer */
+#define US_SENSE_SIZE		18	/* Size of the autosense data buffer */
  
 typedef int (*trans_cmnd)(struct scsi_cmnd *, struct us_data*);
 typedef int (*trans_reset)(struct us_data*);
@@ -168,6 +169,7 @@
 	struct usb_ctrlrequest	*cr;		 /* control requests	 */
 	struct usb_sg_request	current_sg;	 /* scatter-gather req.  */
 	unsigned char		*iobuf;		 /* I/O buffer		 */
+	unsigned char		*sensebuf;	 /* sense data buffer	 */
 	dma_addr_t		cr_dma;		 /* buffer DMA addresses */
 	dma_addr_t		iobuf_dma;
...	...	@@ -636,11 +636,11 @@
636	636
637	637	/* use the new buffer we have */
638	638	old_request_buffer = srb->request_buffer;
639		- srb->request_buffer = srb->sense_buffer;
	639	+ srb->request_buffer = us->sensebuf;
640	640
641	641	/* set the buffer length for transfer */
642	642	old_request_bufflen = srb->request_bufflen;
643		- srb->request_bufflen = 18;
	643	+ srb->request_bufflen = US_SENSE_SIZE;
644	644
645	645	/* set up for no scatter-gather use */
646	646	old_sg = srb->use_sg;
...	...	@@ -652,6 +652,7 @@
652	652	temp_result = us->transport(us->srb, us);
653	653
654	654	/* let's clean up right away */
	655	+ memcpy(srb->sense_buffer, us->sensebuf, US_SENSE_SIZE);
655	656	srb->resid = old_resid;
656	657	srb->request_buffer = old_request_buffer;
657	658	srb->request_bufflen = old_request_bufflen;
...	...	@@ -467,6 +467,12 @@
467	467	US_DEBUGP("I/O buffer allocation failed\n");
468	468	return -ENOMEM;
469	469	}
	470	+
	471	+ us->sensebuf = kmalloc(US_SENSE_SIZE, GFP_KERNEL);
	472	+ if (!us->sensebuf) {
	473	+ US_DEBUGP("Sense buffer allocation failed\n");
	474	+ return -ENOMEM;
	475	+ }
470	476	return 0;
471	477	}
472	478
...	...	@@ -799,6 +805,8 @@
799	805	static void dissociate_dev(struct us_data *us)
800	806	{
801	807	US_DEBUGP("-- %s\n", __FUNCTION__);
	808	+
	809	+ kfree(us->sensebuf);
802	810
803	811	/* Free the device-related DMA-mapped buffers */
804	812	if (us->cr)
...	...	@@ -117,6 +117,7 @@
117	117	*/
118	118
119	119	#define US_IOBUF_SIZE 64 /* Size of the DMA-mapped I/O buffer */
	120	+#define US_SENSE_SIZE 18 /* Size of the autosense data buffer */
120	121
121	122	typedef int (trans_cmnd)(struct scsi_cmnd , struct us_data*);
122	123	typedef int (trans_reset)(struct us_data);
...	...	@@ -168,6 +169,7 @@
168	169	struct usb_ctrlrequest cr; / control requests */
169	170	struct usb_sg_request current_sg; /* scatter-gather req. */
170	171	unsigned char iobuf; / I/O buffer */
	172	+ unsigned char sensebuf; / sense data buffer */
171	173	dma_addr_t cr_dma; /* buffer DMA addresses */
172	174	dma_addr_t iobuf_dma;
173	175