Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757226Ab0BRTgA (ORCPT ); Thu, 18 Feb 2010 14:36:00 -0500 Received: from ixro-out-rtc.ixiacom.com ([92.87.192.98]:24111 "EHLO ixro-ex1.ixiacom.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752341Ab0BRTf6 (ORCPT ); Thu, 18 Feb 2010 14:35:58 -0500 From: Octavian Purdila To: David Miller Cc: Octavian Purdila , Linux Kernel Network Developers , Linux Kernel Developers , WANG Cong , "Eric W. Biederman" Subject: [net-next PATCH v5 2/3] sysctl: add proc_do_large_bitmap Date: Fri, 19 Feb 2010 00:32:26 +0200 Message-Id: <1266532346-11604-1-git-send-email-opurdila@ixiacom.com> X-Mailer: git-send-email 1.5.6.5 X-OriginalArrivalTime: 18 Feb 2010 19:35:57.0541 (UTC) FILETIME=[97D45950:01CAB0D1] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4424 Lines: 169 The new function can be used to read/write large bitmaps via /proc. A comma separated range format is used for compact output and input (e.g. 1,3-4,10-10). Writing into the file will first reset the bitmap then update it based on the given input. Signed-off-by: Octavian Purdila Cc: WANG Cong Cc: Eric W. Biederman --- include/linux/sysctl.h | 2 + kernel/sysctl.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 124 insertions(+), 0 deletions(-) diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index f66014c..7bb5cb6 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -980,6 +980,8 @@ extern int proc_doulongvec_minmax(struct ctl_table *, int, void __user *, size_t *, loff_t *); extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void __user *, size_t *, loff_t *); +extern int proc_do_large_bitmap(struct ctl_table *, int, + void __user *, size_t *, loff_t *); /* * Register a set of sysctl names by calling register_sysctl_table diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 5259727..ef2c13d 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2635,6 +2635,128 @@ static int proc_do_cad_pid(struct ctl_table *table, int write, return 0; } +/** + * proc_do_large_bitmap - read/write from/to a large bitmap + * @table: the sysctl table + * @write: %TRUE if this is a write to the sysctl file + * @buffer: the user buffer + * @lenp: the size of the user buffer + * @ppos: file position + * + * The bitmap is stored at table->data and the bitmap length (in bits) + * in table->maxlen. + * + * We use a range comma separated format (e.g. 1,3-4,10-10) so that + * large bitmaps may be represented in a compact manner. Writing into + * the file will clear the bitmap then update it with the given input. + * + * Returns 0 on success. + */ +int proc_do_large_bitmap(struct ctl_table *table, int write, + void __user *_buffer, size_t *lenp, loff_t *ppos) +{ + bool first = 1; + unsigned long *bitmap = (unsigned long *) table->data; + unsigned long bitmap_len = table->maxlen; + int left = *lenp, err = 0; + char __user *buffer = (char __user *) _buffer; + char tr_a[] = { '-', ',', 0 }, tr_b[] = { ',', 0 }, c; + + + if (!bitmap_len || !left || (*ppos && !write)) { + *lenp = 0; + return 0; + } + + if (write) { + bitmap_clear(bitmap, 0, bitmap_len); + err = proc_skip_wspace(&buffer, &left); + while (!err && left) { + unsigned long val_a, val_b; + bool neg; + + err = proc_get_ulong(&buffer, &left, tr_a, + &val_a, &neg, &c); + if (err) + break; + + if (val_a >= bitmap_len || neg) { + err = -EINVAL; + break; + } + + if (!left || c != '-') { + if (c == ',') { + buffer++; + left--; + } + val_b = val_a; + goto update; + } + + /* skip the - */ + buffer++; left--; + + err = proc_get_ulong(&buffer, &left, tr_b, + &val_b, &neg, &c); + if (err) + break; + + if (val_b >= bitmap_len || neg || val_a > val_b) { + err = -EINVAL; + break; + } + + if (left && c == ',') { + buffer++; + left--; + } + +update: + while (val_a <= val_b) + set_bit(val_a++, bitmap); + + first = 0; val_b++; + } + if (!err) + err = proc_skip_wspace(&buffer, &left); + } else { + unsigned long bit_a, bit_b = 0; + + while (left) { + bit_a = find_next_bit(bitmap, bitmap_len, bit_b); + if (bit_a >= bitmap_len) + break; + bit_b = find_next_zero_bit(bitmap, bitmap_len, + bit_a + 1) - 1; + + err = proc_put_ulong(&buffer, &left, bit_a, 0, first, + ','); + if (err) + break; + if (bit_a != bit_b) { + err = proc_put_char(&buffer, &left, '-'); + if (err) + break; + err = proc_put_ulong(&buffer, &left, bit_b, 0, + 1, 0); + if (err) + break; + } + + first = 0; bit_b++; + } + if (!err) + err = proc_put_char(&buffer, &left, '\n'); + } + + if (write && first) + return err; + *lenp -= left; + *ppos += *lenp; + return 0; +} + #else /* CONFIG_PROC_FS */ int proc_dostring(struct ctl_table *table, int write, -- 1.5.6.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/