Make kimage_load_normal_segment and kexec_update_segment share code
which they currently duplicate.

Signed-off-by: Thiago Jung Bauermann <bauer...@linux.vnet.ibm.com>
---
 kernel/kexec_core.c | 159 +++++++++++++++++++++++++++++++---------------------
 1 file changed, 95 insertions(+), 64 deletions(-)

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 8781d3e4479d..281d8b961fb4 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -700,6 +700,65 @@ static struct page *kimage_alloc_page(struct kimage *image,
        return page;
 }
 
+struct kimage_update_buffer_state {
+       /* Destination memory address currently being copied to. */
+       unsigned long maddr;
+
+       /* Bytes in buffer still left to copy. */
+       size_t ubytes;
+
+       /* Bytes in memory still left to copy. */
+       size_t mbytes;
+
+       /* If true, copy from kbuf. */
+       bool from_kernel;
+
+       /* Clear pages before copying? */
+       bool clear_pages;
+
+       /* Buffer position to continue copying from. */
+       const unsigned char *kbuf;
+       const unsigned char __user *buf;
+};
+
+static int kimage_update_page(struct page *page,
+                             struct kimage_update_buffer_state *state)
+{
+       char *ptr;
+       int result = 0;
+       size_t uchunk, mchunk;
+
+       ptr = kmap(page);
+
+       /* Start with a clear page */
+       if (state->clear_pages)
+               clear_page(ptr);
+
+       ptr += state->maddr & ~PAGE_MASK;
+       mchunk = min_t(size_t, state->mbytes,
+                      PAGE_SIZE - (state->maddr & ~PAGE_MASK));
+       uchunk = min(state->ubytes, mchunk);
+
+       if (state->from_kernel)
+               memcpy(ptr, state->kbuf, uchunk);
+       else
+               result = copy_from_user(ptr, state->buf, uchunk);
+
+       kunmap(page);
+       if (result)
+               return -EFAULT;
+
+       state->ubytes -= uchunk;
+       state->maddr += mchunk;
+       if (state->from_kernel)
+               state->kbuf += mchunk;
+       else
+               state->buf += mchunk;
+       state->mbytes -= mchunk;
+
+       return 0;
+}
+
 /**
  * kexec_update_segment - update the contents of a kimage segment
  * @buffer:    New contents of the segment.
@@ -718,6 +777,7 @@ int kexec_update_segment(const char *buffer, unsigned long 
bufsz,
        unsigned long entry;
        unsigned long *ptr = NULL;
        void *dest = NULL;
+       struct kimage_update_buffer_state state;
 
        for (i = 0; i < kexec_image->nr_segments; i++)
                /* We only support updating whole segments. */
@@ -736,8 +796,15 @@ int kexec_update_segment(const char *buffer, unsigned long 
bufsz,
                return -EINVAL;
        }
 
-       for (entry = kexec_image->head; !(entry & IND_DONE) && memsz;
-            entry = *ptr++) {
+       state.maddr = load_addr;
+       state.ubytes = bufsz;
+       state.mbytes = memsz;
+       state.kbuf = buffer;
+       state.from_kernel = true;
+       state.clear_pages = false;
+
+       for (entry = kexec_image->head; !(entry & IND_DONE) &&
+                                       state.mbytes; entry = *ptr++) {
                void *addr = (void *) (entry & PAGE_MASK);
 
                switch (entry & IND_FLAGS) {
@@ -754,26 +821,13 @@ int kexec_update_segment(const char *buffer, unsigned 
long bufsz,
                                return -EINVAL;
                        }
 
-                       if (dest == (void *) load_addr) {
-                               struct page *page;
-                               char *ptr;
-                               size_t uchunk, mchunk;
-
-                               page = kmap_to_page(addr);
-
-                               ptr = kmap(page);
-                               ptr += load_addr & ~PAGE_MASK;
-                               mchunk = min_t(size_t, memsz,
-                                              PAGE_SIZE - (load_addr & 
~PAGE_MASK));
-                               uchunk = min(bufsz, mchunk);
-                               memcpy(ptr, buffer, uchunk);
-
-                               kunmap(page);
+                       if (dest == (void *) state.maddr) {
+                               int ret;
 
-                               bufsz -= uchunk;
-                               load_addr += mchunk;
-                               buffer += mchunk;
-                               memsz -= mchunk;
+                               ret = kimage_update_page(kmap_to_page(addr),
+                                                        &state);
+                               if (ret)
+                                       return ret;
                        }
                        dest += PAGE_SIZE;
                }
@@ -791,31 +845,30 @@ int kexec_update_segment(const char *buffer, unsigned 
long bufsz,
 static int kimage_load_normal_segment(struct kimage *image,
                                         struct kexec_segment *segment)
 {
-       unsigned long maddr;
-       size_t ubytes, mbytes;
-       int result;
-       unsigned char __user *buf = NULL;
-       unsigned char *kbuf = NULL;
-
-       result = 0;
-       if (image->file_mode)
-               kbuf = segment->kbuf;
-       else
-               buf = segment->buf;
-       ubytes = segment->bufsz;
-       mbytes = segment->memsz;
-       maddr = segment->mem;
+       int result = 0;
+       struct kimage_update_buffer_state state;
+
+       /* For file based kexec, source pages are in kernel memory */
+       if (image->file_mode) {
+               state.kbuf = segment->kbuf;
+               state.from_kernel = true;
+       } else {
+               state.buf = segment->buf;
+               state.from_kernel = false;
+       }
+       state.ubytes = segment->bufsz;
+       state.mbytes = segment->memsz;
+       state.maddr = segment->mem;
+       state.clear_pages = true;
 
-       result = kimage_set_destination(image, maddr);
+       result = kimage_set_destination(image, state.maddr);
        if (result < 0)
                goto out;
 
-       while (mbytes) {
+       while (state.mbytes) {
                struct page *page;
-               char *ptr;
-               size_t uchunk, mchunk;
 
-               page = kimage_alloc_page(image, GFP_HIGHUSER, maddr);
+               page = kimage_alloc_page(image, GFP_HIGHUSER, state.maddr);
                if (!page) {
                        result  = -ENOMEM;
                        goto out;
@@ -825,31 +878,9 @@ static int kimage_load_normal_segment(struct kimage *image,
                if (result < 0)
                        goto out;
 
-               ptr = kmap(page);
-               /* Start with a clear page */
-               clear_page(ptr);
-               ptr += maddr & ~PAGE_MASK;
-               mchunk = min_t(size_t, mbytes,
-                               PAGE_SIZE - (maddr & ~PAGE_MASK));
-               uchunk = min(ubytes, mchunk);
-
-               /* For file based kexec, source pages are in kernel memory */
-               if (image->file_mode)
-                       memcpy(ptr, kbuf, uchunk);
-               else
-                       result = copy_from_user(ptr, buf, uchunk);
-               kunmap(page);
-               if (result) {
-                       result = -EFAULT;
+               result = kimage_update_page(page, &state);
+               if (result)
                        goto out;
-               }
-               ubytes -= uchunk;
-               maddr  += mchunk;
-               if (image->file_mode)
-                       kbuf += mchunk;
-               else
-                       buf += mchunk;
-               mbytes -= mchunk;
        }
 out:
        return result;
-- 
1.9.1

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