libnvme: abstract memory (de)allocation API

[igaw]

This is based on #3310 which does too many things in one patch.
Split the patch into baby steps and see how things go.

• replace dprintf
• platform support for mem allocation helpers
• [ ]

[Copilot]

Pull request overview

This PR refactors memory allocation helpers to be provided by libnvme (with OS-specific implementations) and updates nvme-cli/plugins to use the new libnvme_alloc*() APIs, as part of incremental work toward Windows builds. It also adjusts libnvme logging to avoid dprintf().

Changes:

• Remove the legacy util/mem.* helpers and switch call sites to libnvme_alloc(), libnvme_realloc(), and libnvme_alloc_huge() (plus struct libnvme_mem_huge).
• Introduce nvme/mem.h in libnvme and add Linux/Windows implementations (mem-linux.c, mem-win.c), exporting the new symbols.
• Replace dprintf()-based logging with asprintf() + write().

Reviewed changes

Copilot reviewed 26 out of 26 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
util/meson.build	Drops util/mem.c from util build sources.
util/mem.h	Removes legacy util allocation API header.
util/cleanup.h	Switches __cleanup_huge to libnvme_free_huge.
plugins/zns/zns.c	Migrates huge allocation usage to libnvme (libnvme_alloc_huge, libnvme_mem_huge).
plugins/wdc/wdc-nvme.c	Migrates allocation helpers to libnvme APIs.
plugins/solidigm/solidigm-internal-logs.c	Migrates allocation helpers to libnvme APIs.
plugins/scaleflux/sfx-nvme.c	Migrates huge allocation helpers to libnvme APIs.
plugins/ocp/ocp-nvme.c	Migrates allocation helpers to libnvme APIs.
plugins/micron/micron-nvme.c	Migrates huge allocation helper to libnvme API.
plugins/lm/lm-nvme.c	Migrates huge allocation helper to libnvme API and updates error text.
plugins/ibm/ibm-nvme.c	Migrates allocation helper to libnvme API.
plugins/feat/feat-nvme.c	Migrates allocation helper to libnvme API.
nvme.h	Removes include of deleted util/mem.h.
nvme.c	Migrates many allocations to libnvme APIs and updates huge allocation types.
libnvme/src/nvme/util.c	Removes internal __libnvme_alloc/__libnvme_realloc implementation.
libnvme/src/nvme/tree.c	Switches identify-buffer allocation to libnvme_alloc().
libnvme/src/nvme/private.h	Drops declarations for removed __libnvme_alloc/__libnvme_realloc.
libnvme/src/nvme/nvme-cmds.c	Switches allocations to libnvme_alloc/libnvme_realloc.
libnvme/src/nvme/mem.h	Adds public libnvme memory allocation API header.
libnvme/src/nvme/mem-win.c	Adds Windows implementation of libnvme memory allocation helpers.
libnvme/src/nvme/mem-linux.c	Updates Linux implementation to new libnvme allocation API + exports.
libnvme/src/nvme/log.c	Replaces dprintf() logging with formatted buffer + write().
libnvme/src/nvme/fabrics.c	Switches allocations to libnvme_alloc().
libnvme/src/meson.build	Adds mem sources per-OS and installs new nvme/mem.h.
libnvme/src/libnvme.ld	Exports new libnvme_alloc*()/libnvme_free*() symbols and reorders some entries.
libnvme/src/libnvme.h.in	Installs nvme/mem.h in the public libnvme umbrella header.

Comments suppressed due to low confidence (2)

libnvme/src/nvme/mem-linux.c:43

• libnvme_realloc() calls malloc_usable_size(p) before checking whether p is NULL, but nvme/mem.h documents that passing NULL should behave like libnvme_alloc(). Guard p == NULL first to avoid undefined behavior.
  nvme.c:2905
• The allocation failure check is inverted: this returns false when ctrl is non-NULL (allocation succeeded), and then proceeds with a NULL ctrl when allocation fails. This should be if (!ctrl) return false; (or equivalent).

	__cleanup_free struct nvme_id_ctrl *ctrl = libnvme_alloc(sizeof(*ctrl));

	if (ctrl)
		return false;

	err = nvme_identify_ctrl(hdl, ctrl);
	if (err)
		return false;

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[Copilot]

Pull request overview

Copilot reviewed 29 out of 29 changed files in this pull request and generated 4 comments.

Comments suppressed due to low confidence (3)

nvme.c:2903

• This check is inverted: ctrl is non-NULL on successful allocation, so the function always returns false and never calls nvme_identify_ctrl(). This should be if (!ctrl) return false;.

	__cleanup_libnvme_free struct nvme_id_ctrl *ctrl = libnvme_alloc(sizeof(*ctrl));

	if (ctrl)
		return false;

	err = nvme_identify_ctrl(hdl, ctrl);

libnvme/src/nvme/mem-linux.c:43

• libnvme_realloc() calls malloc_usable_size(p) unconditionally; if p is NULL this is undefined behavior, and it also violates the documented behavior that NULL should act like libnvme_alloc(). Add an early if (!p) return libnvme_alloc(len); before calling malloc_usable_size().
  libnvme/src/nvme/mem-linux.c:19
• This file uses memset/memcpy but doesn’t include <string.h>, which can cause build failures due to missing prototypes. Add the appropriate header include.

[bgoing-micron-oss]

I found today during some testing that _msize was incorrect for working with aligned allocations. There is an _aligned_msize that needs to be used instead.

Suggested change

	old_len = _msize(p);
	old_len = _aligned_msize(p, getpagesize(), 0);

[igaw]

alright, I'll pick up this version then :)

[igaw]

merged these patches separately.