Messages in this thread | | | Date | Wed, 2 Jun 2021 15:22:17 +0100 | From | Jonathan Cameron <> | Subject | Re: [PATCH v2 1/3] lib: bitmap: introduce bitmap_print_to_buf |
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On Wed, 2 Jun 2021 21:48:52 +0800 Tian Tao <tiantao6@hisilicon.com> wrote:
> New API bitmap_print_to_buf() with bin_attribute to avoid maskp > exceeding PAGE_SIZE. bitmap_print_to_pagebuf() is a special case > of bitmap_print_to_buf(), so in bitmap_print_to_pagebuf() call > bitmap_print_to_buf(). > > Signed-off-by: Tian Tao <tiantao6@hisilicon.com> Hi,
I think you need strlen() + 1 as strlen() doesn't include the null terminator. Also good to add () in a few more places to make the hyperlinks work in the html docs (fairly sure it needs those)
I don't really like the fact we can't get the string length without that extra call (as it's buried in the kasprintf() implementation) but this is unlikely to be a high performance path so clean code is better.
Otherwise, LGTM
> --- > include/linux/bitmap.h | 3 +++ > include/linux/cpumask.h | 21 +++++++++++++++++++++ > lib/bitmap.c | 38 ++++++++++++++++++++++++++++++++++++-- > 3 files changed, 60 insertions(+), 2 deletions(-) > > diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h > index 70a9324..bc401bd9b 100644 > --- a/include/linux/bitmap.h > +++ b/include/linux/bitmap.h > @@ -219,6 +219,9 @@ extern unsigned int bitmap_ord_to_pos(const unsigned long *bitmap, unsigned int > extern int bitmap_print_to_pagebuf(bool list, char *buf, > const unsigned long *maskp, int nmaskbits); > > +extern int bitmap_print_to_buf(bool list, char *buf, > + const unsigned long *maskp, int nmaskbits, loff_t off, size_t count); > + > #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1))) > #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1))) > > diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h > index 383684e..56852f2 100644 > --- a/include/linux/cpumask.h > +++ b/include/linux/cpumask.h > @@ -928,6 +928,27 @@ cpumap_print_to_pagebuf(bool list, char *buf, const struct cpumask *mask) > nr_cpu_ids); > } > > +/** > + * cpumap_print_to_buf - copies the cpumask into the buffer either > + * as comma-separated list of cpus or hex values of cpumask > + * @list: indicates whether the cpumap must be list > + * @mask: the cpumask to copy > + * @buf: the buffer to copy into > + * @off: in the string from which we are copying, We copy to @buf + off > + * @count: the maximum number of bytes to print > + * > + * The role of cpumap_print_to_buf and cpumap_print_to_pagebuf is
cpumap_print_to_buf() + other cases of the same so that hyperlinks work in the html docs.
> + * the same, the difference is that buf of bitmap_print_to_buf > + * can be more than one pagesize. > + */ > +static inline ssize_t > +cpumap_print_to_buf(bool list, char *buf, const struct cpumask *mask, > + loff_t off, size_t count) > +{ > + return bitmap_print_to_buf(list, buf, cpumask_bits(mask), > + nr_cpu_ids, off, count); > +} > + > #if NR_CPUS <= BITS_PER_LONG > #define CPU_MASK_ALL \ > (cpumask_t) { { \ > diff --git a/lib/bitmap.c b/lib/bitmap.c > index 75006c4..cb64e66 100644 > --- a/lib/bitmap.c > +++ b/lib/bitmap.c > @@ -460,6 +460,40 @@ int bitmap_parse_user(const char __user *ubuf, > EXPORT_SYMBOL(bitmap_parse_user); > > /** > + * bitmap_print_to_buf - convert bitmap to list or hex format ASCII string > + * @list: indicates whether the bitmap must be list > + * @buf: the kernel space buffer to read to > + * @maskp: pointer to bitmap to convert > + * @nmaskbits: size of bitmap, in bits > + * @off: offset in data buffer below > + * @count: the maximum number of bytes to print > + * > + * The role of bitmap_print_to_buf and bitmap_print_to_pagebuf() is > + * the same, the difference is that buf of bitmap_print_to_buf() > + * can be more than one pagesize. > + */ > +int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp, > + int nmaskbits, loff_t off, size_t count) > +{ > + int size; > + void *data; > + const char *fmt = list ? "%*pbl\n" : "%*pb\n"; > + > + if (off == LLONG_MAX && count == PAGE_SIZE - offset_in_page(buf)) > + return scnprintf(buf, count, fmt, nmaskbits, maskp); > + > + data = kasprintf(GFP_KERNEL, fmt, nmaskbits, maskp); > + if (!data) > + return -ENOMEM; > + > + size = memory_read_from_buffer(buf, count, &off, data, strlen(data));
strlen(data) + 1 I think...
> + kfree(data); > + > + return size; > +} > +EXPORT_SYMBOL(bitmap_print_to_buf); > + > +/** > * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string > * @list: indicates whether the bitmap must be list > * @buf: page aligned buffer into which string is placed > @@ -480,8 +514,8 @@ int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp, > { > ptrdiff_t len = PAGE_SIZE - offset_in_page(buf); > > - return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) : > - scnprintf(buf, len, "%*pb\n", nmaskbits, maskp); > + return bitmap_print_to_buf(list, buf, maskp, nmaskbits, > + LLONG_MAX, len); > } > EXPORT_SYMBOL(bitmap_print_to_pagebuf); >
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