X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=drivers%2Fscsi%2Fscsi_lib.c;h=bdce9d1f5b7152ff7ec2b573e6522fefe5cb4d33;hb=f0cd91a68acdc9b49d7f6738b514a426da627649;hp=faee4757c03adb712363eb09527c5af357c0bef3;hpb=128e6ced247cda88f96fa9f2e4ba8b2c4a681560;p=powerpc.git

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index faee4757c0..bdce9d1f5b 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -30,7 +30,7 @@
 #include "scsi_logging.h"
 
 
-#define SG_MEMPOOL_NR		(sizeof(scsi_sg_pools)/sizeof(struct scsi_host_sg_pool))
+#define SG_MEMPOOL_NR		ARRAY_SIZE(scsi_sg_pools)
 #define SG_MEMPOOL_SIZE		32
 
 struct scsi_host_sg_pool {
@@ -2363,3 +2363,61 @@ scsi_target_unblock(struct device *dev)
 		device_for_each_child(dev, NULL, target_unblock);
 }
 EXPORT_SYMBOL_GPL(scsi_target_unblock);
+
+/**
+ * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
+ * @sg:		scatter-gather list
+ * @sg_count:	number of segments in sg
+ * @offset:	offset in bytes into sg, on return offset into the mapped area
+ * @len:	bytes to map, on return number of bytes mapped
+ *
+ * Returns virtual address of the start of the mapped page
+ */
+void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
+			  size_t *offset, size_t *len)
+{
+	int i;
+	size_t sg_len = 0, len_complete = 0;
+	struct page *page;
+
+	for (i = 0; i < sg_count; i++) {
+		len_complete = sg_len; /* Complete sg-entries */
+		sg_len += sg[i].length;
+		if (sg_len > *offset)
+			break;
+	}
+
+	if (unlikely(i == sg_count)) {
+		printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
+			"elements %d\n",
+		       __FUNCTION__, sg_len, *offset, sg_count);
+		WARN_ON(1);
+		return NULL;
+	}
+
+	/* Offset starting from the beginning of first page in this sg-entry */
+	*offset = *offset - len_complete + sg[i].offset;
+
+	/* Assumption: contiguous pages can be accessed as "page + i" */
+	page = nth_page(sg[i].page, (*offset >> PAGE_SHIFT));
+	*offset &= ~PAGE_MASK;
+
+	/* Bytes in this sg-entry from *offset to the end of the page */
+	sg_len = PAGE_SIZE - *offset;
+	if (*len > sg_len)
+		*len = sg_len;
+
+	return kmap_atomic(page, KM_BIO_SRC_IRQ);
+}
+EXPORT_SYMBOL(scsi_kmap_atomic_sg);
+
+/**
+ * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously
+ *			   mapped with scsi_kmap_atomic_sg
+ * @virt:	virtual address to be unmapped
+ */
+void scsi_kunmap_atomic_sg(void *virt)
+{
+	kunmap_atomic(virt, KM_BIO_SRC_IRQ);
+}
+EXPORT_SYMBOL(scsi_kunmap_atomic_sg);