[src/trunk]: src/sys/opencrypto redo result buffer allocation, to avoid dynam...

[drochner <drochner%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/295920458c84
branches:  trunk
changeset: 762291:295920458c84
user:      drochner <drochner%NetBSD.org@localhost>
date:      Fri Feb 18 22:02:09 2011 +0000

description:
redo result buffer allocation, to avoid dynamic allocations:
-use exponentially growing buffer sizes instead of just linear extension
-drop the dynamic allocation of buffer metadata introduced in rev.1.8 --
 if the initial array is not sufficient something is wrong
-apply some (arbitrary, heuristic) limit so that compressed data
 which extract into insane amounts of constant data don't kill the system
This addresses PR kern/36864 by Wolfgang Stukenbrock. Some tuning
might be useful, but hopefully this is an improvement already.

diffstat:

 sys/opencrypto/deflate.c |  33 +++++++++------------------------
 1 files changed, 9 insertions(+), 24 deletions(-)

diffs (89 lines):

diff -r 3f6110e0e12b -r 295920458c84 sys/opencrypto/deflate.c
--- a/sys/opencrypto/deflate.c  Fri Feb 18 21:38:17 2011 +0000
+++ b/sys/opencrypto/deflate.c  Fri Feb 18 22:02:09 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: deflate.c,v 1.17 2011/02/18 10:50:56 drochner Exp $ */
+/*     $NetBSD: deflate.c,v 1.18 2011/02/18 22:02:09 drochner Exp $ */
 /*     $FreeBSD: src/sys/opencrypto/deflate.c,v 1.1.2.1 2002/11/21 23:34:23 sam Exp $  */
 /* $OpenBSD: deflate.c,v 1.3 2001/08/20 02:45:22 hugh Exp $ */
 
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: deflate.c,v 1.17 2011/02/18 10:50:56 drochner Exp $");
+__KERNEL_RCSID(0, "$NetBSD: deflate.c,v 1.18 2011/02/18 22:02:09 drochner Exp $");
 
 #include <sys/types.h>
 #include <sys/malloc.h>
@@ -79,16 +79,10 @@
        u_int8_t *output;
        u_int32_t count, result, tocopy;
        int error, i, j;
-       struct deflate_buf *buf, *tmp;
-       size_t len;
+       struct deflate_buf buf[ZBUF];
 
        DPRINTF(("deflate_global: size %d\n", size));
 
-       len = ZBUF;
-       buf = malloc(len*sizeof(struct deflate_buf), M_CRYPTO_DATA, M_NOWAIT);
-       if (buf == NULL)
-               return 0;
-
        memset(&zbuf, 0, sizeof(z_stream));
        zbuf.next_in = data;    /* data that is going to be processed */
        zbuf.zalloc = ocf_zalloc;
@@ -110,7 +104,7 @@
        }
        buf[0].out = malloc(buf[0].size, M_CRYPTO_DATA, M_NOWAIT);
        if (buf[0].out == NULL)
-               goto bad3;
+               return 0;
        i = 1;
 
        zbuf.next_out = buf[0].out;
@@ -142,21 +136,15 @@
                else if (error != Z_OK)
                        goto bad;
                else if (zbuf.avail_out == 0) {
-                       if (i == len) {
-                               len += ZBUF;
-                               tmp = realloc(buf,len*sizeof(struct deflate_buf),
-                                                         M_CRYPTO_DATA, M_NOWAIT);
-                               if (tmp == NULL)
-                                       goto bad;
-                               buf = tmp;
-                       }
                        /* we need more output space, allocate size */
-                       buf[i].out = malloc(size, M_CRYPTO_DATA, M_NOWAIT);
+                       int nextsize = buf[i-1].size * 2;
+                       if (i == ZBUF || nextsize > 1000000)
+                               goto bad;
+                       buf[i].out = malloc(nextsize, M_CRYPTO_DATA, M_NOWAIT);
                        if (buf[i].out == NULL)
                                goto bad;
                        zbuf.next_out = buf[i].out;
-                       buf[i].size = size;
-                       zbuf.avail_out = buf[i].size;
+                       zbuf.avail_out = buf[i].size = nextsize;
                        i++;
                }
        }
@@ -181,7 +169,6 @@
        } else {
                *out = buf[0].out;
        }
-       free(buf, M_CRYPTO_DATA);
        if (decomp)
                inflateEnd(&zbuf);
        else
@@ -196,8 +183,6 @@
 bad2:
        for (j = 0; j < i; j++)
                free(buf[j].out, M_CRYPTO_DATA);
-bad3:
-       free(buf, M_CRYPTO_DATA);
        return 0;
 }