From 12f86b5b3e1bdf75e0a467d771c16cc42f3a1f1a Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Mon, 7 Nov 2016 19:13:37 +0800 Subject: [PATCH] nvdimm acpi: drop the lock of fit buffer as there is a global lock to protect vm-exit handlers and QMP/monitor, this lock can be dropped Suggested-by: Igor Mammedov Signed-off-by: Xiao Guangrong Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Stefan Hajnoczi Reviewed-by: Igor Mammedov --- hw/acpi/nvdimm.c | 11 +---------- include/hw/mem/nvdimm.h | 17 +++++------------ 2 files changed, 6 insertions(+), 22 deletions(-) diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c index 623bb36..0fe3547 100644 --- a/hw/acpi/nvdimm.c +++ b/hw/acpi/nvdimm.c @@ -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, diff --git a/include/hw/mem/nvdimm.h b/include/hw/mem/nvdimm.h index 33cd421..d3ffb25 100644 --- a/include/hw/mem/nvdimm.h +++ b/include/hw/mem/nvdimm.h @@ -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; }; -- 2.7.4