diff options
| author | John Ogness <john.ogness@linutronix.de> | 2020-09-14 14:39:52 +0206 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2020-09-15 15:52:49 +0200 |
| commit | 10dcb06d40411a73e1ae111717e9a987bb760313 (patch) | |
| tree | 21520d9beb051c2215ce29d03a30e180b6e78cd7 /kernel/printk/printk_ringbuffer.h | |
| parent | cc5c7041c6e1fe8c02fe9e16f28a5e52f7a6957c (diff) | |
printk: ringbuffer: change representation of states
Rather than deriving the state by evaluating bits within the flags
area of the state variable, assign the states explicit values and
set those values in the flags area. Introduce macros to make it
simple to read and write state values for the state variable.
Although the functionality is preserved, the binary representation
for the states is changed.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200914123354.832-5-john.ogness@linutronix.de
Diffstat (limited to 'kernel/printk/printk_ringbuffer.h')
| -rw-r--r-- | kernel/printk/printk_ringbuffer.h | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/kernel/printk/printk_ringbuffer.h b/kernel/printk/printk_ringbuffer.h index e6302da041f9..a9d85a6727b1 100644 --- a/kernel/printk/printk_ringbuffer.h +++ b/kernel/printk/printk_ringbuffer.h @@ -112,16 +112,25 @@ struct prb_reserved_entry { unsigned int text_space; }; -#define _DATA_SIZE(sz_bits) (1UL << (sz_bits)) -#define _DESCS_COUNT(ct_bits) (1U << (ct_bits)) -#define DESC_SV_BITS (sizeof(unsigned long) * 8) -#define DESC_COMMITTED_MASK (1UL << (DESC_SV_BITS - 1)) -#define DESC_REUSE_MASK (1UL << (DESC_SV_BITS - 2)) -#define DESC_FLAGS_MASK (DESC_COMMITTED_MASK | DESC_REUSE_MASK) -#define DESC_ID_MASK (~DESC_FLAGS_MASK) -#define DESC_ID(sv) ((sv) & DESC_ID_MASK) -#define FAILED_LPOS 0x1 -#define NO_LPOS 0x3 +/* The possible responses of a descriptor state-query. */ +enum desc_state { + desc_miss = -1, /* ID mismatch (pseudo state) */ + desc_reserved = 0x0, /* reserved, in use by writer */ + desc_committed = 0x1, /* committed by writer */ + desc_reusable = 0x3, /* free, not yet used by any writer */ +}; + +#define _DATA_SIZE(sz_bits) (1UL << (sz_bits)) +#define _DESCS_COUNT(ct_bits) (1U << (ct_bits)) +#define DESC_SV_BITS (sizeof(unsigned long) * 8) +#define DESC_FLAGS_SHIFT (DESC_SV_BITS - 2) +#define DESC_FLAGS_MASK (3UL << DESC_FLAGS_SHIFT) +#define DESC_STATE(sv) (3UL & (sv >> DESC_FLAGS_SHIFT)) +#define DESC_SV(id, state) (((unsigned long)state << DESC_FLAGS_SHIFT) | id) +#define DESC_ID_MASK (~DESC_FLAGS_MASK) +#define DESC_ID(sv) ((sv) & DESC_ID_MASK) +#define FAILED_LPOS 0x1 +#define NO_LPOS 0x3 #define FAILED_BLK_LPOS \ { \ @@ -213,7 +222,7 @@ struct prb_reserved_entry { */ #define BLK0_LPOS(sz_bits) (-(_DATA_SIZE(sz_bits))) #define DESC0_ID(ct_bits) DESC_ID(-(_DESCS_COUNT(ct_bits) + 1)) -#define DESC0_SV(ct_bits) (DESC_COMMITTED_MASK | DESC_REUSE_MASK | DESC0_ID(ct_bits)) +#define DESC0_SV(ct_bits) DESC_SV(DESC0_ID(ct_bits), desc_reusable) /* * Define a ringbuffer with an external text data buffer. The same as |