s390/zcore: simplify memcpy_hsa

Replace the three part copy logic int memcpy_hsa with a single loop
around sclp_sdias_copy with appropriate offset and size calculations,
and inline memcpy_hsa into memcpy_hsa_user and memcpy_hsa_kernel.

Acked-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c
index 4fa455787a7756458a43891f7e9ba04dfb3504cf..7d94c696c38beaee614a04f7373a6be474cc4a70 100644 (file)
--- a/drivers/s390/char/zcore.c
+++ b/drivers/s390/char/zcore.c
@@ -34,8 +34,6 @@
 
 #define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)
 
-#define TO_USER                1
-#define TO_KERNEL      0
 #define CHUNK_INFO_SIZE        34 /* 2 16-byte char, each followed by blank */
 
 enum arch_id {
@@ -56,88 +54,38 @@ static struct dentry *zcore_reipl_file;
 static struct dentry *zcore_hsa_file;
 static struct ipl_parameter_block *ipl_block;
 
+static char hsa_buf[PAGE_SIZE] __aligned(PAGE_SIZE);
+
 /*
- * Copy memory from HSA to kernel or user memory (not reentrant):
+ * Copy memory from HSA to user memory (not reentrant):
  *
- * @dest:  Kernel or user buffer where memory should be copied to
+ * @dest:  User buffer where memory should be copied to
  * @src:   Start address within HSA where data should be copied
  * @count: Size of buffer, which should be copied
- * @mode:  Either TO_KERNEL or TO_USER
  */
-static int memcpy_hsa(void *dest, unsigned long src, size_t count, int mode)
+int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count)
 {
-       int offs, blk_num;
-       static char buf[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
+       unsigned long offset, bytes;
 
        if (!hsa_available)
                return -ENODATA;
-       if (count == 0)
-               return 0;
-
-       /* copy first block */
-       offs = 0;
-       if ((src % PAGE_SIZE) != 0) {
-               blk_num = src / PAGE_SIZE + 2;
-               if (sclp_sdias_copy(buf, blk_num, 1)) {
-                       TRACE("sclp_sdias_copy() failed\n");
-                       return -EIO;
-               }
-               offs = min((PAGE_SIZE - (src % PAGE_SIZE)), count);
-               if (mode == TO_USER) {
-                       if (copy_to_user((__force __user void*) dest,
-                                        buf + (src % PAGE_SIZE), offs))
-                               return -EFAULT;
-               } else
-                       memcpy(dest, buf + (src % PAGE_SIZE), offs);
-       }
-       if (offs == count)
-               goto out;
 
-       /* copy middle */
-       for (; (offs + PAGE_SIZE) <= count; offs += PAGE_SIZE) {
-               blk_num = (src + offs) / PAGE_SIZE + 2;
-               if (sclp_sdias_copy(buf, blk_num, 1)) {
+       while (count) {
+               if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
                        TRACE("sclp_sdias_copy() failed\n");
                        return -EIO;
                }
-               if (mode == TO_USER) {
-                       if (copy_to_user((__force __user void*) dest + offs,
-                                        buf, PAGE_SIZE))
-                               return -EFAULT;
-               } else
-                       memcpy(dest + offs, buf, PAGE_SIZE);
-       }
-       if (offs == count)
-               goto out;
-
-       /* copy last block */
-       blk_num = (src + offs) / PAGE_SIZE + 2;
-       if (sclp_sdias_copy(buf, blk_num, 1)) {
-               TRACE("sclp_sdias_copy() failed\n");
-               return -EIO;
-       }
-       if (mode == TO_USER) {
-               if (copy_to_user((__force __user void*) dest + offs, buf,
-                                count - offs))
+               offset = src % PAGE_SIZE;
+               bytes = min(PAGE_SIZE - offset, count);
+               if (copy_to_user(dest, hsa_buf + offset, bytes))
                        return -EFAULT;
-       } else
-               memcpy(dest + offs, buf, count - offs);
-out:
+               src += bytes;
+               dest += bytes;
+               count -= bytes;
+       }
        return 0;
 }
 
-/*
- * Copy memory from HSA to user memory (not reentrant):
- *
- * @dest:  Kernel or user buffer where memory should be copied to
- * @src:   Start address within HSA where data should be copied
- * @count: Size of buffer, which should be copied
- */
-int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count)
-{
-       return memcpy_hsa((void __force *) dest, src, count, TO_USER);
-}
-
 /*
  * Copy memory from HSA to kernel memory (not reentrant):
  *
@@ -147,7 +95,24 @@ int memcpy_hsa_user(void __user *dest, unsigned long src, size_t count)
  */
 int memcpy_hsa_kernel(void *dest, unsigned long src, size_t count)
 {
-       return memcpy_hsa(dest, src, count, TO_KERNEL);
+       unsigned long offset, bytes;
+
+       if (!hsa_available)
+               return -ENODATA;
+
+       while (count) {
+               if (sclp_sdias_copy(hsa_buf, src / PAGE_SIZE + 2, 1)) {
+                       TRACE("sclp_sdias_copy() failed\n");
+                       return -EIO;
+               }
+               offset = src % PAGE_SIZE;
+               bytes = min(PAGE_SIZE - offset, count);
+               memcpy(dest, hsa_buf + offset, bytes);
+               src += bytes;
+               dest += bytes;
+               count -= bytes;
+       }
+       return 0;
 }
 
 static int __init init_cpu_info(void)