These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / lib / scatterlist.c

diff --git a/kernel/lib/scatterlist.c b/kernel/lib/scatterlist.c
index f6d1f88..ebe3b7e 100644 (file)
--- a/kernel/lib/scatterlist.c
+++ b/kernel/lib/scatterlist.c
@@ -56,6 +56,38 @@ int sg_nents(struct scatterlist *sg)
 }
 EXPORT_SYMBOL(sg_nents);
 
+/**
+ * sg_nents_for_len - return total count of entries in scatterlist
+ *                    needed to satisfy the supplied length
+ * @sg:                The scatterlist
+ * @len:       The total required length
+ *
+ * Description:
+ * Determines the number of entries in sg that are required to meet
+ * the supplied length, taking into acount chaining as well
+ *
+ * Returns:
+ *   the number of sg entries needed, negative error on failure
+ *
+ **/
+int sg_nents_for_len(struct scatterlist *sg, u64 len)
+{
+       int nents;
+       u64 total;
+
+       if (!len)
+               return 0;
+
+       for (nents = 0, total = 0; sg; sg = sg_next(sg)) {
+               nents++;
+               total += sg->length;
+               if (total >= len)
+                       return nents;
+       }
+
+       return -EINVAL;
+}
+EXPORT_SYMBOL(sg_nents_for_len);
 
 /**
  * sg_last - return the last scatterlist entry in a list
@@ -73,16 +105,12 @@ EXPORT_SYMBOL(sg_nents);
  **/
 struct scatterlist *sg_last(struct scatterlist *sgl, unsigned int nents)
 {
-#ifndef CONFIG_ARCH_HAS_SG_CHAIN
-       struct scatterlist *ret = &sgl[nents - 1];
-#else
        struct scatterlist *sg, *ret = NULL;
        unsigned int i;
 
        for_each_sg(sgl, sg, nents, i)
                ret = sg;
 
-#endif
 #ifdef CONFIG_DEBUG_SG
        BUG_ON(sgl[0].sg_magic != SG_MAGIC);
        BUG_ON(!sg_is_last(ret));
@@ -618,9 +646,8 @@ EXPORT_SYMBOL(sg_miter_stop);
  * Returns the number of copied bytes.
  *
  **/
-static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
-                            void *buf, size_t buflen, off_t skip,
-                            bool to_buffer)
+size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf,
+                     size_t buflen, off_t skip, bool to_buffer)
 {
        unsigned int offset = 0;
        struct sg_mapping_iter miter;
@@ -657,6 +684,7 @@ static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
        local_irq_restore_nort(flags);
        return offset;
 }
+EXPORT_SYMBOL(sg_copy_buffer);
 
 /**
  * sg_copy_from_buffer - Copy from a linear buffer to an SG list
@@ -669,9 +697,9 @@ static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
  *
  **/
 size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,
-                          void *buf, size_t buflen)
+                          const void *buf, size_t buflen)
 {
-       return sg_copy_buffer(sgl, nents, buf, buflen, 0, false);
+       return sg_copy_buffer(sgl, nents, (void *)buf, buflen, 0, false);
 }
 EXPORT_SYMBOL(sg_copy_from_buffer);
 
@@ -697,16 +725,16 @@ EXPORT_SYMBOL(sg_copy_to_buffer);
  * @sgl:                The SG list
  * @nents:              Number of SG entries
  * @buf:                Where to copy from
- * @skip:               Number of bytes to skip before copying
  * @buflen:             The number of bytes to copy
+ * @skip:               Number of bytes to skip before copying
  *
  * Returns the number of copied bytes.
  *
  **/
 size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents,
-                           void *buf, size_t buflen, off_t skip)
+                           const void *buf, size_t buflen, off_t skip)
 {
-       return sg_copy_buffer(sgl, nents, buf, buflen, skip, false);
+       return sg_copy_buffer(sgl, nents, (void *)buf, buflen, skip, false);
 }
 EXPORT_SYMBOL(sg_pcopy_from_buffer);
 
@@ -715,8 +743,8 @@ EXPORT_SYMBOL(sg_pcopy_from_buffer);
  * @sgl:                The SG list
  * @nents:              Number of SG entries
  * @buf:                Where to copy to
- * @skip:               Number of bytes to skip before copying
  * @buflen:             The number of bytes to copy
+ * @skip:               Number of bytes to skip before copying
  *
  * Returns the number of copied bytes.
  *