Messages in this thread Patch in this message | | | Date | Mon, 10 Mar 2003 18:48:44 -0800 | From | "Randy.Dunlap" <> | Subject | [PATCH] vt_ioctl() stack size reduction (v2) |
| |
Hi,
This patch (to 2.5.64) reduces stack size usage in drivers/char/vt_ioctl.c::vt_ioctl() from 0x334 bytes to 0xec bytes (P4, UP, gcc 2.96).
James, are you the maintainer of this module?
Comments, anyone?
Thanks to Ingo Oeser for one suggestion -- applied.
~Randypatch_name: vt_ioctl_stack3.patch patch_version: 2003-03-10.18:12:21 author: Randy.Dunlap <rddunlap@osdl.org> description: reduces stack usage in drivers/char/vt_ioctl.c::vt_ioctl() from 0x334 bytes to 0xec bytes (P4, UP, gcc 2.96) product_versions: linux-2564 changelog: share one console_font_op structure throughout the ioctl(); kmalloc() the kbsentry struct (513 bytes); requires: Linux 2.5.64 maintainer: jsimmons@users.sf.net, jsimmons@infradead.org diffstat: = drivers/char/vt_ioctl.c | 104 ++++++++++++++++++++++++++++-------------------- 1 files changed, 62 insertions(+), 42 deletions(-)
diff -Naur ./drivers/char/vt_ioctl.c%VTSTK ./drivers/char/vt_ioctl.c --- ./drivers/char/vt_ioctl.c%VTSTK Tue Mar 4 19:29:31 2003 +++ ./drivers/char/vt_ioctl.c Mon Mar 10 18:08:32 2003 @@ -191,38 +191,56 @@ static inline int do_kdgkb_ioctl(int cmd, struct kbsentry *user_kdgkb, int perm) { - struct kbsentry tmp; + struct kbsentry *kbs; char *p; u_char *q; int sz; int delta; char *first_free, *fj, *fnw; int i, j, k; + int ret; + + kbs = kmalloc(sizeof(*kbs), GFP_KERNEL); + if (!kbs) { + ret = -ENOMEM; + goto reterr; + } /* we mostly copy too much here (512bytes), but who cares ;) */ - if (copy_from_user(&tmp, user_kdgkb, sizeof(struct kbsentry))) - return -EFAULT; - tmp.kb_string[sizeof(tmp.kb_string)-1] = '\0'; - if (tmp.kb_func >= MAX_NR_FUNC) - return -EINVAL; - i = tmp.kb_func; + if (copy_from_user(kbs, user_kdgkb, sizeof(struct kbsentry))) { + ret = -EFAULT; + goto reterr; + } + kbs->kb_string[sizeof(kbs->kb_string)-1] = '\0'; + if (kbs->kb_func >= MAX_NR_FUNC) { + ret = -EINVAL; + goto reterr; + } + i = kbs->kb_func; switch (cmd) { case KDGKBSENT: - sz = sizeof(tmp.kb_string) - 1; /* sz should have been + sz = sizeof(kbs->kb_string) - 1; /* sz should have been a struct member */ q = user_kdgkb->kb_string; p = func_table[i]; if(p) for ( ; *p && sz; p++, sz--) - if (put_user(*p, q++)) - return -EFAULT; - if (put_user('\0', q)) - return -EFAULT; + if (put_user(*p, q++)) { + ret = -EFAULT; + goto reterr; + } + if (put_user('\0', q)) { + ret = -EFAULT; + goto reterr; + } + kfree(kbs); return ((p && *p) ? -EOVERFLOW : 0); case KDSKBSENT: - if (!perm) - return -EPERM; + if (!perm) { + ret = -EPERM; + goto reterr; + } q = func_table[i]; first_free = funcbufptr + (funcbufsize - funcbufleft); @@ -233,7 +251,7 @@ else fj = first_free; - delta = (q ? -strlen(q) : 1) + strlen(tmp.kb_string); + delta = (q ? -strlen(q) : 1) + strlen(kbs->kb_string); if (delta <= funcbufleft) { /* it fits in current buf */ if (j < MAX_NR_FUNC) { memmove(fj + delta, fj, first_free - fj); @@ -249,8 +267,10 @@ while (sz < funcbufsize - funcbufleft + delta) sz <<= 1; fnw = (char *) kmalloc(sz, GFP_KERNEL); - if(!fnw) - return -ENOMEM; + if(!fnw) { + ret = -ENOMEM; + goto reterr; + } if (!q) func_table[i] = fj; @@ -272,17 +292,20 @@ funcbufleft = funcbufleft - delta + sz - funcbufsize; funcbufsize = sz; } - strcpy(func_table[i], tmp.kb_string); + strcpy(func_table[i], kbs->kb_string); break; } - return 0; + ret = 0; + +reterr: + kfree(kbs); + return ret; } static inline int -do_fontx_ioctl(int cmd, struct consolefontdesc *user_cfd, int perm) +do_fontx_ioctl(int cmd, struct consolefontdesc *user_cfd, int perm, struct console_font_op *op) { struct consolefontdesc cfdarg; - struct console_font_op op; int i; if (copy_from_user(&cfdarg, user_cfd, sizeof(struct consolefontdesc))) @@ -292,25 +315,25 @@ case PIO_FONTX: if (!perm) return -EPERM; - op.op = KD_FONT_OP_SET; - op.flags = KD_FONT_FLAG_OLD; - op.width = 8; - op.height = cfdarg.charheight; - op.charcount = cfdarg.charcount; - op.data = cfdarg.chardata; - return con_font_op(fg_console, &op); + op->op = KD_FONT_OP_SET; + op->flags = KD_FONT_FLAG_OLD; + op->width = 8; + op->height = cfdarg.charheight; + op->charcount = cfdarg.charcount; + op->data = cfdarg.chardata; + return con_font_op(fg_console, op); case GIO_FONTX: { - op.op = KD_FONT_OP_GET; - op.flags = KD_FONT_FLAG_OLD; - op.width = 8; - op.height = cfdarg.charheight; - op.charcount = cfdarg.charcount; - op.data = cfdarg.chardata; - i = con_font_op(fg_console, &op); + op->op = KD_FONT_OP_GET; + op->flags = KD_FONT_FLAG_OLD; + op->width = 8; + op->height = cfdarg.charheight; + op->charcount = cfdarg.charcount; + op->data = cfdarg.chardata; + i = con_font_op(fg_console, op); if (i) return i; - cfdarg.charheight = op.height; - cfdarg.charcount = op.charcount; + cfdarg.charheight = op->height; + cfdarg.charcount = op->charcount; if (copy_to_user(user_cfd, &cfdarg, sizeof(struct consolefontdesc))) return -EFAULT; return 0; @@ -355,6 +378,7 @@ unsigned char ucval; struct kbd_struct * kbd; struct vt_struct *vt = (struct vt_struct *)tty->driver_data; + struct console_font_op op; /* used in multiple places here */ console = vt->vc_num; @@ -860,7 +884,6 @@ } case PIO_FONT: { - struct console_font_op op; if (!perm) return -EPERM; op.op = KD_FONT_OP_SET; @@ -873,7 +896,6 @@ } case GIO_FONT: { - struct console_font_op op; op.op = KD_FONT_OP_GET; op.flags = KD_FONT_FLAG_OLD; op.width = 8; @@ -893,7 +915,7 @@ case PIO_FONTX: case GIO_FONTX: - return do_fontx_ioctl(cmd, (struct consolefontdesc *)arg, perm); + return do_fontx_ioctl(cmd, (struct consolefontdesc *)arg, perm, &op); case PIO_FONTRESET: { @@ -906,7 +928,6 @@ return -ENOSYS; #else { - struct console_font_op op; op.op = KD_FONT_OP_SET_DEFAULT; op.data = NULL; i = con_font_op(fg_console, &op); @@ -918,7 +939,6 @@ } case KDFONTOP: { - struct console_font_op op; if (copy_from_user(&op, (void *) arg, sizeof(op))) return -EFAULT; if (!perm && op.op != KD_FONT_OP_GET) | |