/* * linux/drivers/video/bt431.h * * Copyright 2003 Thiemo Seufer * Copyright 2016 Maciej W. Rozycki * * This file is subject to the terms and conditions of the GNU General * Public License. See the file COPYING in the main directory of this * archive for more details. */ #include #define BT431_CURSOR_SIZE 64 /* * Bt431 cursor generator registers, 32-bit aligned. * Two twin Bt431 are used on the DECstation's PMAG-AA. */ struct bt431_regs { volatile u16 addr_lo; u16 pad0; volatile u16 addr_hi; u16 pad1; volatile u16 addr_cmap; u16 pad2; volatile u16 addr_reg; u16 pad3; }; static inline u16 bt431_set_value(u8 val) { return ((val << 8) | (val & 0xff)) & 0xffff; } static inline u8 bt431_get_value(u16 val) { return val & 0xff; } /* * Additional registers addressed indirectly. */ #define BT431_REG_CMD 0x0000 #define BT431_REG_CXLO 0x0001 #define BT431_REG_CXHI 0x0002 #define BT431_REG_CYLO 0x0003 #define BT431_REG_CYHI 0x0004 #define BT431_REG_WXLO 0x0005 #define BT431_REG_WXHI 0x0006 #define BT431_REG_WYLO 0x0007 #define BT431_REG_WYHI 0x0008 #define BT431_REG_WWLO 0x0009 #define BT431_REG_WWHI 0x000a #define BT431_REG_WHLO 0x000b #define BT431_REG_WHHI 0x000c #define BT431_REG_CRAM_BASE 0x0000 #define BT431_REG_CRAM_END 0x01ff /* * Command register. */ #define BT431_CMD_CURS_ENABLE 0x40 #define BT431_CMD_XHAIR_ENABLE 0x20 #define BT431_CMD_OR_CURSORS 0x10 #define BT431_CMD_XOR_CURSORS 0x00 #define BT431_CMD_1_1_MUX 0x00 #define BT431_CMD_4_1_MUX 0x04 #define BT431_CMD_5_1_MUX 0x08 #define BT431_CMD_xxx_MUX 0x0c #define BT431_CMD_THICK_1 0x00 #define BT431_CMD_THICK_3 0x01 #define BT431_CMD_THICK_5 0x02 #define BT431_CMD_THICK_7 0x03 static inline void bt431_select_reg(struct bt431_regs *regs, int ir) { /* * The compiler splits the write in two bytes without these * helper variables. */ volatile u16 *lo = &(regs->addr_lo); volatile u16 *hi = &(regs->addr_hi); mb(); *lo = bt431_set_value(ir & 0xff); wmb(); *hi = bt431_set_value((ir >> 8) & 0xff); } /* Autoincrement read/write. */ static inline u8 bt431_read_reg_inc(struct bt431_regs *regs) { /* * The compiler splits the write in two bytes without the * helper variable. */ volatile u16 *r = &(regs->addr_reg); mb(); return bt431_get_value(*r); } static inline void bt431_write_reg_inc(struct bt431_regs *regs, u8 value) { /* * The compiler splits the write in two bytes without the * helper variable. */ volatile u16 *r = &(regs->addr_reg); mb(); *r = bt431_set_value(value); } static inline u8 bt431_read_reg(struct bt431_regs *regs, int ir) { bt431_select_reg(regs, ir); return bt431_read_reg_inc(regs); } static inline void bt431_write_reg(struct bt431_regs *regs, int ir, u8 value) { bt431_select_reg(regs, ir); bt431_write_reg_inc(regs, value); } /* Autoincremented read/write for the cursor map. */ static inline u16 bt431_read_cmap_inc(struct bt431_regs *regs) { /* * The compiler splits the write in two bytes without the * helper variable. */ volatile u16 *r = &(regs->addr_cmap); mb(); return *r; } static inline void bt431_write_cmap_inc(struct bt431_regs *regs, u16 value) { /* * The compiler splits the write in two bytes without the * helper variable. */ volatile u16 *r = &(regs->addr_cmap); mb(); *r = value; } static inline u16 bt431_read_cmap(struct bt431_regs *regs, int cr) { bt431_select_reg(regs, cr); return bt431_read_cmap_inc(regs); } static inline void bt431_write_cmap(struct bt431_regs *regs, int cr, u16 value) { bt431_select_reg(regs, cr); bt431_write_cmap_inc(regs, value); } static inline void bt431_enable_cursor(struct bt431_regs *regs) { bt431_write_reg(regs, BT431_REG_CMD, BT431_CMD_CURS_ENABLE | BT431_CMD_OR_CURSORS | BT431_CMD_4_1_MUX | BT431_CMD_THICK_1); } static inline void bt431_erase_cursor(struct bt431_regs *regs) { bt431_write_reg(regs, BT431_REG_CMD, BT431_CMD_4_1_MUX); } static inline void bt431_position_cursor(struct bt431_regs *regs, u16 x, u16 y) { /* * Magic from the MACH sources. * * Cx = x + D + H - P * P = 37 if 1:1, 52 if 4:1, 57 if 5:1 * D = pixel skew between outdata and external data * H = pixels between HSYNCH falling and active video * * Cy = y + V - 32 * V = scanlines between HSYNCH falling, two or more * clocks after VSYNCH falling, and active video */ x += 412 - 52; y += 68 - 32; /* Use autoincrement. */ bt431_select_reg(regs, BT431_REG_CXLO); bt431_write_reg_inc(regs, x & 0xff); /* BT431_REG_CXLO */ bt431_write_reg_inc(regs, (x >> 8) & 0x0f); /* BT431_REG_CXHI */ bt431_write_reg_inc(regs, y & 0xff); /* BT431_REG_CYLO */ bt431_write_reg_inc(regs, (y >> 8) & 0x0f); /* BT431_REG_CYHI */ } static inline void bt431_set_cursor(struct bt431_regs *regs, const char *data, const char *mask, u16 rop, u16 width, u16 height) { u16 x, y; int i; i = 0; width = DIV_ROUND_UP(width, 8); bt431_select_reg(regs, BT431_REG_CRAM_BASE); for (y = 0; y < BT431_CURSOR_SIZE; y++) for (x = 0; x < BT431_CURSOR_SIZE / 8; x++) { u16 val = 0; if (y < height && x < width) { val = mask[i]; if (rop == ROP_XOR) val = (val << 8) | (val ^ data[i]); else val = (val << 8) | (val & data[i]); i++; } bt431_write_cmap_inc(regs, val); } } static inline void bt431_init_cursor(struct bt431_regs *regs) { /* no crosshair window */ bt431_select_reg(regs, BT431_REG_WXLO); bt431_write_reg_inc(regs, 0x00); /* BT431_REG_WXLO */ bt431_write_reg_inc(regs, 0x00); /* BT431_REG_WXHI */ bt431_write_reg_inc(regs, 0x00); /* BT431_REG_WYLO */ bt431_write_reg_inc(regs, 0x00); /* BT431_REG_WYHI */ bt431_write_reg_inc(regs, 0x00); /* BT431_REG_WWLO */ bt431_write_reg_inc(regs, 0x00); /* BT431_REG_WWHI */ bt431_write_reg_inc(regs, 0x00); /* BT431_REG_WHLO */ bt431_write_reg_inc(regs, 0x00); /* BT431_REG_WHHI */ } ph/osdmap.c?h=nds-private-remove&id=1b1bc42c1692e9b62756323c675a44cb1a1f9dbd'>1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (diff)
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return "true" IFF they acquire a reference. But the return value from atomic_long_inc_not_zero() is a long and may have high bits set, e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'net/ceph/osdmap.c')