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kernel: do preparation work for copyless read/write

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Matheus
2024-09-18 21:17:37 -03:00
parent 1140244816
commit 611f13b562
12 changed files with 134 additions and 47 deletions
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kernel-src/io/acpi/dev.c
+10 -17
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@@ -7,15 +7,11 @@
static ringbuffer_t ringbuffer;
static pollheader_t pollheader;
static spinlock_t lock;
static mutex_t mutex;
void acpi_signaldevice(char c) {
long ipl = spinlock_acquireraiseipl(&lock, IPL_DPC);
if (ringbuffer_write(&ringbuffer, &c, 1))
poll_event(&pollheader, POLLIN);
spinlock_releaseloweripl(&lock, ipl);
}
static int internalpoll(polldata_t *data, int events) {
@@ -43,13 +39,11 @@ static int read(int minor, void *buffer, size_t size, uintmax_t offset, int flag
if (error)
return error;
MUTEX_ACQUIRE(&mutex, false);
for (;;) {
long ipl = spinlock_acquireraiseipl(&lock, IPL_DPC);
int revents = internalpoll(&desc.data[0], POLLIN);
spinlock_releaseloweripl(&lock, ipl);
if (revents)
break;
@@ -66,13 +60,14 @@ static int read(int minor, void *buffer, size_t size, uintmax_t offset, int flag
poll_leave(&desc);
}
long ipl = spinlock_acquireraiseipl(&lock, IPL_DPC);
// this abuses a behavior of how the ringbuffer works to not need a lock for reading
// (as it would need interrupts to be off)
*readc = ringbuffer_read(&ringbuffer, buffer, size);
spinlock_releaseloweripl(&lock, ipl);
if (*readc == RINGBUFFER_USER_COPY_FAILED)
error = EFAULT;
leave:
MUTEX_RELEASE(&mutex);
poll_leave(&desc);
poll_destroydesc(&desc);
return error;
@@ -98,11 +93,9 @@ static int write(int minor, void *buffer, size_t size, uintmax_t offset, int fla
}
static int poll(int minor, polldata_t *data, int events) {
long ipl = spinlock_acquireraiseipl(&lock, IPL_DPC);
MUTEX_ACQUIRE(&mutex, false);
int revents = internalpoll(data, events);
spinlock_releaseloweripl(&lock, ipl);
MUTEX_RELEASE(&mutex);
return revents;
}