Re: [PATCH 4/6] perf/aux: Make perf_event accessible to setup_aux()

From: kbuild test robot
Date: Mon Jul 02 2018 - 22:06:10 EST


Hi Mathieu,

I love your patch! Yet something to improve:

[auto build test ERROR on tip/perf/core]
[also build test ERROR on v4.18-rc3 next-20180702]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/Mathieu-Poirier/perf-Add-ioctl-for-PMU-driver-configuration/20180703-064327
config: s390-defconfig (attached as .config)
compiler: s390x-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.2.0 make.cross ARCH=s390

All error/warnings (new ones prefixed by >>):

>> arch/s390/kernel/perf_cpum_sf.c:1606:1: error: expected identifier or '(' before '{' token
{
^
>> arch/s390/kernel/perf_cpum_sf.c:1604:14: warning: 'aux_buffer_setup' used but never defined
static void *aux_buffer_setup(struct perf_event *event, void **pages,
^~~~~~~~~~~~~~~~

vim +1606 arch/s390/kernel/perf_cpum_sf.c

ca5955cd Pu Hou 2016-11-11 1589
ca5955cd Pu Hou 2016-11-11 1590 /*
ca5955cd Pu Hou 2016-11-11 1591 * aux_buffer_setup() - Setup AUX buffer for diagnostic mode sampling
ca5955cd Pu Hou 2016-11-11 1592 * @cpu: On which to allocate, -1 means current
ca5955cd Pu Hou 2016-11-11 1593 * @pages: Array of pointers to buffer pages passed from perf core
ca5955cd Pu Hou 2016-11-11 1594 * @nr_pages: Total pages
ca5955cd Pu Hou 2016-11-11 1595 * @snapshot: Flag for snapshot mode
ca5955cd Pu Hou 2016-11-11 1596 *
ca5955cd Pu Hou 2016-11-11 1597 * This is the callback when setup an event using AUX buffer. Perf tool can
ca5955cd Pu Hou 2016-11-11 1598 * trigger this by an additional mmap() call on the event. Unlike the buffer
ca5955cd Pu Hou 2016-11-11 1599 * for basic samples, AUX buffer belongs to the event. It is scheduled with
ca5955cd Pu Hou 2016-11-11 1600 * the task among online cpus when it is a per-thread event.
ca5955cd Pu Hou 2016-11-11 1601 *
ca5955cd Pu Hou 2016-11-11 1602 * Return the private AUX buffer structure if success or NULL if fails.
ca5955cd Pu Hou 2016-11-11 1603 */
ceb39bf0 Mathieu Poirier 2018-07-02 @1604 static void *aux_buffer_setup(struct perf_event *event, void **pages,
ceb39bf0 Mathieu Poirier 2018-07-02 1605 int nr_pages, bool snapshot);
ca5955cd Pu Hou 2016-11-11 @1606 {
ca5955cd Pu Hou 2016-11-11 1607 struct sf_buffer *sfb;
ca5955cd Pu Hou 2016-11-11 1608 struct aux_buffer *aux;
ca5955cd Pu Hou 2016-11-11 1609 unsigned long *new, *tail;
ca5955cd Pu Hou 2016-11-11 1610 int i, n_sdbt;
ca5955cd Pu Hou 2016-11-11 1611
ca5955cd Pu Hou 2016-11-11 1612 if (!nr_pages || !pages)
ca5955cd Pu Hou 2016-11-11 1613 return NULL;
ca5955cd Pu Hou 2016-11-11 1614
ca5955cd Pu Hou 2016-11-11 1615 if (nr_pages > CPUM_SF_MAX_SDB * CPUM_SF_SDB_DIAG_FACTOR) {
ca5955cd Pu Hou 2016-11-11 1616 pr_err("AUX buffer size (%i pages) is larger than the "
ca5955cd Pu Hou 2016-11-11 1617 "maximum sampling buffer limit\n",
ca5955cd Pu Hou 2016-11-11 1618 nr_pages);
ca5955cd Pu Hou 2016-11-11 1619 return NULL;
ca5955cd Pu Hou 2016-11-11 1620 } else if (nr_pages < CPUM_SF_MIN_SDB * CPUM_SF_SDB_DIAG_FACTOR) {
ca5955cd Pu Hou 2016-11-11 1621 pr_err("AUX buffer size (%i pages) is less than the "
ca5955cd Pu Hou 2016-11-11 1622 "minimum sampling buffer limit\n",
ca5955cd Pu Hou 2016-11-11 1623 nr_pages);
ca5955cd Pu Hou 2016-11-11 1624 return NULL;
ca5955cd Pu Hou 2016-11-11 1625 }
ca5955cd Pu Hou 2016-11-11 1626
ca5955cd Pu Hou 2016-11-11 1627 /* Allocate aux_buffer struct for the event */
ca5955cd Pu Hou 2016-11-11 1628 aux = kmalloc(sizeof(struct aux_buffer), GFP_KERNEL);
ca5955cd Pu Hou 2016-11-11 1629 if (!aux)
ca5955cd Pu Hou 2016-11-11 1630 goto no_aux;
ca5955cd Pu Hou 2016-11-11 1631 sfb = &aux->sfb;
ca5955cd Pu Hou 2016-11-11 1632
ca5955cd Pu Hou 2016-11-11 1633 /* Allocate sdbt_index for fast reference */
ca5955cd Pu Hou 2016-11-11 1634 n_sdbt = (nr_pages + CPUM_SF_SDB_PER_TABLE - 1) / CPUM_SF_SDB_PER_TABLE;
ca5955cd Pu Hou 2016-11-11 1635 aux->sdbt_index = kmalloc_array(n_sdbt, sizeof(void *), GFP_KERNEL);
ca5955cd Pu Hou 2016-11-11 1636 if (!aux->sdbt_index)
ca5955cd Pu Hou 2016-11-11 1637 goto no_sdbt_index;
ca5955cd Pu Hou 2016-11-11 1638
ca5955cd Pu Hou 2016-11-11 1639 /* Allocate sdb_index for fast reference */
ca5955cd Pu Hou 2016-11-11 1640 aux->sdb_index = kmalloc_array(nr_pages, sizeof(void *), GFP_KERNEL);
ca5955cd Pu Hou 2016-11-11 1641 if (!aux->sdb_index)
ca5955cd Pu Hou 2016-11-11 1642 goto no_sdb_index;
ca5955cd Pu Hou 2016-11-11 1643
ca5955cd Pu Hou 2016-11-11 1644 /* Allocate the first SDBT */
ca5955cd Pu Hou 2016-11-11 1645 sfb->num_sdbt = 0;
ca5955cd Pu Hou 2016-11-11 1646 sfb->sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL);
ca5955cd Pu Hou 2016-11-11 1647 if (!sfb->sdbt)
ca5955cd Pu Hou 2016-11-11 1648 goto no_sdbt;
ca5955cd Pu Hou 2016-11-11 1649 aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)sfb->sdbt;
ca5955cd Pu Hou 2016-11-11 1650 tail = sfb->tail = sfb->sdbt;
ca5955cd Pu Hou 2016-11-11 1651
ca5955cd Pu Hou 2016-11-11 1652 /*
ca5955cd Pu Hou 2016-11-11 1653 * Link the provided pages of AUX buffer to SDBT.
ca5955cd Pu Hou 2016-11-11 1654 * Allocate SDBT if needed.
ca5955cd Pu Hou 2016-11-11 1655 */
ca5955cd Pu Hou 2016-11-11 1656 for (i = 0; i < nr_pages; i++, tail++) {
ca5955cd Pu Hou 2016-11-11 1657 if (require_table_link(tail)) {
ca5955cd Pu Hou 2016-11-11 1658 new = (unsigned long *) get_zeroed_page(GFP_KERNEL);
ca5955cd Pu Hou 2016-11-11 1659 if (!new)
ca5955cd Pu Hou 2016-11-11 1660 goto no_sdbt;
ca5955cd Pu Hou 2016-11-11 1661 aux->sdbt_index[sfb->num_sdbt++] = (unsigned long)new;
ca5955cd Pu Hou 2016-11-11 1662 /* Link current page to tail of chain */
ca5955cd Pu Hou 2016-11-11 1663 *tail = (unsigned long)(void *) new + 1;
ca5955cd Pu Hou 2016-11-11 1664 tail = new;
ca5955cd Pu Hou 2016-11-11 1665 }
ca5955cd Pu Hou 2016-11-11 1666 /* Tail is the entry in a SDBT */
ca5955cd Pu Hou 2016-11-11 1667 *tail = (unsigned long)pages[i];
ca5955cd Pu Hou 2016-11-11 1668 aux->sdb_index[i] = (unsigned long)pages[i];
ca5955cd Pu Hou 2016-11-11 1669 }
ca5955cd Pu Hou 2016-11-11 1670 sfb->num_sdb = nr_pages;
ca5955cd Pu Hou 2016-11-11 1671
ca5955cd Pu Hou 2016-11-11 1672 /* Link the last entry in the SDBT to the first SDBT */
ca5955cd Pu Hou 2016-11-11 1673 *tail = (unsigned long) sfb->sdbt + 1;
ca5955cd Pu Hou 2016-11-11 1674 sfb->tail = tail;
ca5955cd Pu Hou 2016-11-11 1675
ca5955cd Pu Hou 2016-11-11 1676 /*
ca5955cd Pu Hou 2016-11-11 1677 * Initial all SDBs are zeroed. Mark it as empty.
ca5955cd Pu Hou 2016-11-11 1678 * So there is no need to clear the full indicator
ca5955cd Pu Hou 2016-11-11 1679 * when this event is first added.
ca5955cd Pu Hou 2016-11-11 1680 */
ca5955cd Pu Hou 2016-11-11 1681 aux->empty_mark = sfb->num_sdb - 1;
ca5955cd Pu Hou 2016-11-11 1682
ca5955cd Pu Hou 2016-11-11 1683 debug_sprintf_event(sfdbg, 4, "aux_buffer_setup: setup %lu SDBTs"
ca5955cd Pu Hou 2016-11-11 1684 " and %lu SDBs\n",
ca5955cd Pu Hou 2016-11-11 1685 sfb->num_sdbt, sfb->num_sdb);
ca5955cd Pu Hou 2016-11-11 1686
ca5955cd Pu Hou 2016-11-11 1687 return aux;
ca5955cd Pu Hou 2016-11-11 1688
ca5955cd Pu Hou 2016-11-11 1689 no_sdbt:
ca5955cd Pu Hou 2016-11-11 1690 /* SDBs (AUX buffer pages) are freed by caller */
ca5955cd Pu Hou 2016-11-11 1691 for (i = 0; i < sfb->num_sdbt; i++)
ca5955cd Pu Hou 2016-11-11 1692 free_page(aux->sdbt_index[i]);
ca5955cd Pu Hou 2016-11-11 1693 kfree(aux->sdb_index);
ca5955cd Pu Hou 2016-11-11 1694 no_sdb_index:
ca5955cd Pu Hou 2016-11-11 1695 kfree(aux->sdbt_index);
ca5955cd Pu Hou 2016-11-11 1696 no_sdbt_index:
ca5955cd Pu Hou 2016-11-11 1697 kfree(aux);
ca5955cd Pu Hou 2016-11-11 1698 no_aux:
ca5955cd Pu Hou 2016-11-11 1699 return NULL;
ca5955cd Pu Hou 2016-11-11 1700 }
ca5955cd Pu Hou 2016-11-11 1701

:::::: The code at line 1606 was first introduced by commit
:::::: ca5955cdeae744edd3dcc65d677e833fc29658c2 s390/cpumf: introduce AUX buffer for dump diagnostic sample data

:::::: TO: Pu Hou <bjhoupu@xxxxxxxxxxxxxxxxxx>
:::::: CC: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>

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