From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- sound/firewire/lib.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 72 insertions(+) create mode 100644 sound/firewire/lib.c (limited to 'sound/firewire/lib.c') diff --git a/sound/firewire/lib.c b/sound/firewire/lib.c new file mode 100644 index 000000000..654e1a605 --- /dev/null +++ b/sound/firewire/lib.c @@ -0,0 +1,72 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * miscellaneous helper functions + * + * Copyright (c) Clemens Ladisch + */ + +#include +#include +#include +#include +#include +#include "lib.h" + +#define ERROR_RETRY_DELAY_MS 20 + +/** + * snd_fw_transaction - send a request and wait for its completion + * @unit: the driver's unit on the target device + * @tcode: the transaction code + * @offset: the address in the target's address space + * @buffer: input/output data + * @length: length of @buffer + * @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the + * request only in that generation; use %FW_QUIET to suppress error + * messages + * + * Submits an asynchronous request to the target device, and waits for the + * response. The node ID and the current generation are derived from @unit. + * On a bus reset or an error, the transaction is retried a few times. + * Returns zero on success, or a negative error code. + */ +int snd_fw_transaction(struct fw_unit *unit, int tcode, + u64 offset, void *buffer, size_t length, + unsigned int flags) +{ + struct fw_device *device = fw_parent_device(unit); + int generation, rcode, tries = 0; + + generation = flags & FW_GENERATION_MASK; + for (;;) { + if (!(flags & FW_FIXED_GENERATION)) { + generation = device->generation; + smp_rmb(); /* node_id vs. generation */ + } + rcode = fw_run_transaction(device->card, tcode, + device->node_id, generation, + device->max_speed, offset, + buffer, length); + + if (rcode == RCODE_COMPLETE) + return 0; + + if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION)) + return -EAGAIN; + + if (rcode_is_permanent_error(rcode) || ++tries >= 3) { + if (!(flags & FW_QUIET)) + dev_err(&unit->device, + "transaction failed: %s\n", + fw_rcode_string(rcode)); + return -EIO; + } + + msleep(ERROR_RETRY_DELAY_MS); + } +} +EXPORT_SYMBOL(snd_fw_transaction); + +MODULE_DESCRIPTION("FireWire audio helper functions"); +MODULE_AUTHOR("Clemens Ladisch "); +MODULE_LICENSE("GPL"); -- cgit v1.3.1