dump_skip(): dump_seek() replacement taking coredump_params

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

4 files changed, 20 insertions, 40 deletions

diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c
index a4f847f77234..ca0ba15a7306 100644
--- a/fs/binfmt_aout.c
+++ b/fs/binfmt_aout.c
@@ -87,7 +87,7 @@ static int aout_core_dump(struct coredump_params *cprm)
         if (!dump_emit(cprm, &dump, sizeof(dump)))
                 goto end_coredump;
 /* Now dump all of the user data.  Include malloced stuff as well */
-        if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump)))
+        if (!dump_skip(cprm, PAGE_SIZE - sizeof(dump)))
                 goto end_coredump;
 /* now we start writing out the user space info */
         set_fs(USER_DS);
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 4f7dda9d86b5..c56ae3264a65 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -2162,7 +2162,7 @@ static int elf_core_dump(struct coredump_params *cprm)
                 goto end_coredump;
 
         /* Align to page */
-        if (!dump_seek(cprm->file, dataoff - cprm->written))
+        if (!dump_skip(cprm, dataoff - cprm->written))
                 goto end_coredump;
 
         for (vma = first_vma(current, gate_vma); vma != NULL;
@@ -2183,7 +2183,7 @@ static int elf_core_dump(struct coredump_params *cprm)
                                 kunmap(page);
                                 page_cache_release(page);
                         } else
-                                stop = !dump_seek(cprm->file, PAGE_SIZE);
+                                stop = !dump_skip(cprm, PAGE_SIZE);
                         if (stop)
                                 goto end_coredump;
                 }
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 70e299917898..a69fc4ae1c85 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1509,7 +1509,7 @@ static bool elf_fdpic_dump_segments(struct coredump_params *cprm)
                                 kunmap(page);
                                 page_cache_release(page);
                         } else {
-                                res = dump_seek(file, PAGE_SIZE);
+                                res = dump_skip(cprm, PAGE_SIZE);
                         }
                         if (!res)
                                 return false;
@@ -1547,11 +1547,10 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
         int has_dumped = 0;
         mm_segment_t fs;
         int segs;
-        size_t size = 0;
         int i;
         struct vm_area_struct *vma;
         struct elfhdr *elf = NULL;
-        loff_t offset = 0, dataoff, foffset;
+        loff_t offset = 0, dataoff;
         int numnote;
         struct memelfnote *notes = NULL;
         struct elf_prstatus *prstatus = NULL;   /* NT_PRSTATUS */
@@ -1682,7 +1681,6 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
 
         offset += sizeof(*elf);                         /* Elf header */
         offset += segs * sizeof(struct elf_phdr);       /* Program headers */
-        foffset = offset;
 
         /* Write notes phdr entry */
         {
@@ -1751,8 +1749,6 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
         if (!elf_core_write_extra_phdrs(cprm, offset))
                 goto end_coredump;
 
-        size = cprm->written;
-        cprm->written = foffset;
         /* write out the notes section */
         for (i = 0; i < numnote; i++)
                 if (!writenote(notes + i, cprm))
@@ -1768,10 +1764,9 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
                                 goto end_coredump;
         }
 
-        if (!dump_seek(cprm->file, dataoff - cprm->written))
+        if (!dump_skip(cprm, dataoff - cprm->written))
                 goto end_coredump;
 
-        cprm->written = size;
         if (!elf_fdpic_dump_segments(cprm))
                 goto end_coredump;
 
diff --git a/fs/coredump.c b/fs/coredump.c
index 2472ed9e682c..18baf2c009d4 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -685,14 +685,6 @@ fail:
  * do on a core-file: use only these functions to write out all the
  * necessary info.
  */
-int dump_write(struct file *file, const void *addr, int nr)
-{
-        return !dump_interrupted() &&
-                access_ok(VERIFY_READ, addr, nr) &&
-                file->f_op->write(file, addr, nr, &file->f_pos) == nr;
-}
-EXPORT_SYMBOL(dump_write);
-
 int dump_emit(struct coredump_params *cprm, const void *addr, int nr)
 {
         struct file *file = cprm->file;
@@ -714,32 +706,25 @@ int dump_emit(struct coredump_params *cprm, const void *addr, int nr)
 }
 EXPORT_SYMBOL(dump_emit);
 
-int dump_seek(struct file *file, loff_t off)
+int dump_skip(struct coredump_params *cprm, size_t nr)
 {
-        int ret = 1;
-
+        static char zeroes[PAGE_SIZE];
+        struct file *file = cprm->file;
         if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
+                if (cprm->written + nr > cprm->limit)
+                        return 0;
                 if (dump_interrupted() ||
-                    file->f_op->llseek(file, off, SEEK_CUR) < 0)
+                    file->f_op->llseek(file, nr, SEEK_CUR) < 0)
                         return 0;
+                cprm->written += nr;
+                return 1;
         } else {
-                char *buf = (char *)get_zeroed_page(GFP_KERNEL);
-
-                if (!buf)
-                        return 0;
-                while (off > 0) {
-                        unsigned long n = off;
-
-                        if (n > PAGE_SIZE)
-                                n = PAGE_SIZE;
-                        if (!dump_write(file, buf, n)) {
-                                ret = 0;
-                                break;
-                        }
-                        off -= n;
+                while (nr > PAGE_SIZE) {
+                        if (!dump_emit(cprm, zeroes, PAGE_SIZE))
+                                return 0;
+                        nr -= PAGE_SIZE;
                 }
-                free_page((unsigned long)buf);
+                return dump_emit(cprm, zeroes, nr);
         }
-        return ret;
 }
-EXPORT_SYMBOL(dump_seek);
+EXPORT_SYMBOL(dump_skip);