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nvdimm acpi: drop the lock of fit buffer

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as there is a global lock to protect vm-exit handlers and
QMP/monitor, this lock can be dropped

Suggested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
This commit is contained in:
Xiao Guangrong 2016-11-07 19:13:37 +08:00 committed by Michael S. Tsirkin
parent c7f8d0f3a5
commit 12f86b5b3e
2 changed files with 6 additions and 22 deletions
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11
hw/acpi/nvdimm.c
View File

@ -371,17 +371,14 @@ static GArray *nvdimm_build_device_structure(void)
static void nvdimm_init_fit_buffer(NvdimmFitBuffer *fit_buf)
{
qemu_mutex_init(&fit_buf->lock);
fit_buf->fit = g_array_new(false, true /* clear */, 1);
}
static void nvdimm_build_fit_buffer(NvdimmFitBuffer *fit_buf)
{
qemu_mutex_lock(&fit_buf->lock);
g_array_free(fit_buf->fit, true);
fit_buf->fit = nvdimm_build_device_structure();
fit_buf->dirty = true;
qemu_mutex_unlock(&fit_buf->lock);
}
void nvdimm_acpi_hotplug(AcpiNVDIMMState *state)
@ -395,11 +392,10 @@ static void nvdimm_build_nfit(AcpiNVDIMMState *state, GArray *table_offsets,
NvdimmFitBuffer *fit_buf = &state->fit_buf;
unsigned int header;
qemu_mutex_lock(&fit_buf->lock);
/* NVDIMM device is not plugged? */
if (!fit_buf->fit->len) {
goto exit;
return;
}
acpi_add_table(table_offsets, table_data);
@ -413,9 +409,6 @@ static void nvdimm_build_nfit(AcpiNVDIMMState *state, GArray *table_offsets,
build_header(linker, table_data,
(void *)(table_data->data + header), "NFIT",
sizeof(NvdimmNfitHeader) + fit_buf->fit->len, 1, NULL, NULL);
exit:
qemu_mutex_unlock(&fit_buf->lock);
}
struct NvdimmDsmIn {
@ -544,7 +537,6 @@ static void nvdimm_dsm_func_read_fit(AcpiNVDIMMState *state, NvdimmDsmIn *in,
read_fit = (NvdimmFuncReadFITIn *)in->arg3;
le32_to_cpus(&read_fit->offset);
qemu_mutex_lock(&fit_buf->lock);
fit = fit_buf->fit;
nvdimm_debug("Read FIT: offset %#x FIT size %#x Dirty %s.\n",
@ -578,7 +570,6 @@ exit:
cpu_physical_memory_write(dsm_mem_addr, read_fit_out, size);
g_free(read_fit_out);
qemu_mutex_unlock(&fit_buf->lock);
}
static void nvdimm_dsm_reserved_root(AcpiNVDIMMState *state, NvdimmDsmIn *in,

17
include/hw/mem/nvdimm.h
View File

@ -99,20 +99,13 @@ typedef struct NVDIMMClass NVDIMMClass;
#define NVDIMM_ACPI_IO_LEN 4
/*
* The buffer, @fit, saves the FIT info for all the presented NVDIMM
* devices which is updated after the NVDIMM device is plugged or
* unplugged.
*
* Rules to use the buffer:
* 1) the user should hold the @lock to access the buffer.
* 2) mark @dirty whenever the buffer is updated.
*
* These rules preserve NVDIMM ACPI _FIT method to read incomplete
* or obsolete fit info if fit update happens during multiple RFIT
* calls.
* NvdimmFitBuffer:
* @fit: FIT structures for present NVDIMMs. It is updated when
* the NVDIMM device is plugged or unplugged.
* @dirty: It allows OSPM to detect change and restart read in
* progress if there is any.
*/
struct NvdimmFitBuffer {
QemuMutex lock;
GArray *fit;
bool dirty;
};