path: root/lib/inflate.c
diff options
authorThomas Petazzoni <thomas.petazzoni@free-electrons.com>2008-07-25 01:45:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-25 10:53:28 -0700
commit2d6ffcca623a9a16df6cdfbe8250b7a5904a5f5e (patch)
tree70d30cb6516608e9a8a1dce60c59f3a5ff21b305 /lib/inflate.c
parentba92a43dbaee339cf5915ef766d3d3ffbaaf103c (diff)
inflate: refactor inflate malloc code
Inflate requires some dynamic memory allocation very early in the boot process and this is provided with a set of four functions: malloc/free/gzip_mark/gzip_release. The old inflate code used a mark/release strategy rather than implement free. This new version instead keeps a count on the number of outstanding allocations and when it hits zero, it resets the malloc arena. This allows removing all the mark and release implementations and unifying all the malloc/free implementations. The architecture-dependent code must define two addresses: - free_mem_ptr, the address of the beginning of the area in which allocations should be made - free_mem_end_ptr, the address of the end of the area in which allocations should be made. If set to 0, then no check is made on the number of allocations, it just grows as much as needed The architecture-dependent code can also provide an arch_decomp_wdog() function call. This function will be called several times during the decompression process, and allow to notify the watchdog that the system is still running. If an architecture provides such a call, then it must define ARCH_HAS_DECOMP_WDOG so that the generic inflate code calls arch_decomp_wdog(). Work initially done by Matt Mackall, updated to a recent version of the kernel and improved by me. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Cc: Matt Mackall <mpm@selenic.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Mikael Starvik <mikael.starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: David Howells <dhowells@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andi Kleen <andi@firstfloor.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Acked-by: Paul Mundt <lethal@linux-sh.org> Acked-by: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/inflate.c')
1 files changed, 45 insertions, 7 deletions
diff --git a/lib/inflate.c b/lib/inflate.c
index 9762294be06..1a8e8a97812 100644
--- a/lib/inflate.c
+++ b/lib/inflate.c
@@ -230,6 +230,45 @@ STATIC const ush mask_bits[] = {
#define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE())<<k;k+=8;}}
#define DUMPBITS(n) {b>>=(n);k-=(n);}
+/* A trivial malloc implementation, adapted from
+ * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994
+ */
+static unsigned long malloc_ptr;
+static int malloc_count;
+static void *malloc(int size)
+ void *p;
+ if (size < 0)
+ error("Malloc error");
+ if (!malloc_ptr)
+ malloc_ptr = free_mem_ptr;
+ malloc_ptr = (malloc_ptr + 3) & ~3; /* Align */
+ p = (void *)malloc_ptr;
+ malloc_ptr += size;
+ if (free_mem_end_ptr && malloc_ptr >= free_mem_end_ptr)
+ error("Out of memory");
+ malloc_count++;
+ return p;
+static void free(void *where)
+ malloc_count--;
+ if (!malloc_count)
+ malloc_ptr = free_mem_ptr;
+#define malloc(a) kmalloc(a, GFP_KERNEL)
+#define free(a) kfree(a)
Huffman code decoding is performed using a multi-level table lookup.
@@ -1045,7 +1084,6 @@ STATIC int INIT inflate(void)
int e; /* last block flag */
int r; /* result code */
unsigned h; /* maximum struct huft's malloc'ed */
- void *ptr;
/* initialize window, bit buffer */
wp = 0;
@@ -1057,12 +1095,12 @@ STATIC int INIT inflate(void)
h = 0;
do {
hufts = 0;
- gzip_mark(&ptr);
- if ((r = inflate_block(&e)) != 0) {
- gzip_release(&ptr);
- return r;
- }
- gzip_release(&ptr);
+ arch_decomp_wdog();
+ r = inflate_block(&e);
+ if (r)
+ return r;
if (hufts > h)
h = hufts;
} while (!e);